2017-09 Db2 12 SQL Access path: Death by APAR

We recently held one of our Design Councils, this one was all about Db2 12 and going Agile. I was asked the following question after one of my presentations about verifying Db2 Code/Catalog/Function Levels:

“How many APARs really can affect access paths?”

I had to admit that I did not know the answer – I *hate* not knowing things, so I set off to find out how many Db2 Optimizer-relevant APARs there were in 2016 up until today (Oct 17th 2017).

 

Db2 12 APAR review sqlaccesspath

First I used this search argument, as I am only interested in Db2, sqlaccesspath keyword related APARs, those that have an Optimizer relevant CSECT, are HIPER and in Db2 12:

5740xyr00 AND sqlaccesspath AND dsnxo* AND yesHIPER AND C10

1.     PI69349: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query       2017-04-14

 

Remove the yesHIPER and you get 22:


1.     PI82797: LESS FILTERING INDEX SELECTED FOR INNER TABLE OF NESTED LOOP JOIN
A smaller, less filtering index is selected for the inner table with a Nested Loop Join.      2017-10-02

2.     PI78122: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-10-02

3.     PI83289: QUERY ACCESS PATH MAY BE UNPREDICTABLE FOR A QUERY WHERE THERE ARE EQUAL PREDICATES COVERING ALL THE COLUMNS ...
Query access path may be unpredictable for a query where there are equal predicates covering all the columns of a unique index.        2017-09-02

4.     PI83454: INEFFICIENT ACCESS PATH IS USED BECAUSE OF AN INCORRECT COMPOUND FILTER FACTOR OF RANGE PREDICATES
The compound filter factor of two range predicates on the same column is underestimated, that causes an inefficient access      2017-09-02

5.     PI83547: NON-MATCHING INDEX CHOSEN WHEN A MATCHING INDEX EXISTS
A non-matching index could be chosen when an index with good matching exists.    2017-09-02

6.     PI82634: MULTI INDEX ACCESS CHOSEN WHEN A BETTER MATCHING INDEX EXISTS
MULTI-INDEX ACCESS WAS CHOSEN WHEN A MORE EFFICIENT INDEX USING BETTER MATCHING EXISTS.       2017-08-02

7.     PI77792: ABSTRACT:INEFFICIENT ACCESS PATH WITH SORT DISTINCT IN CTE
AN INEFFICIENT ACCESS PATH CAN BE CHOSEN WHEN A SORT FOR DISTINCT IS NEEDED INSIDE A CTE.     2017-06-02

8.     PI73290: Db2 FOR Z/OS USERS OF QUERIES WITH GROUP BY, DISTINCT, IN SUBQUERY OR NOT IN SUBQUERY.
Db2 may choose an inefficient access path as non-matching index access without matching predicates and screening predicates when     2017-05-01

9.     PI73368: ABSTRACT=INEFFICIENT ACCESS PATH WITH SINGLE VALUE PAGE RANGE PREDICATE.An inefficient access path can be chosen when page range access is used for a join predicate and the columns has a cardinality 2017-05-01

10.    PI75966: INEFFICIENT ACCESS PATH IS SELECTED.
List prefetch plan with higher cost may be chosen mistakenly when there is one table in the query block and the index covers        2017-05-01

11.    PI71368: R-SCAN ACCESS PATH CHOSEN OVER MULTI-INDEX ACCESS FOR A TABLE WHICH QUALIFIES FOR NPGTHRSH BEHAVIOR
R-scan access path chosen over multi-index access for a table which qualifies for NPGTHRSH behavior.        2017-04-20

12.    PI75963: ACCESS PATH FOR A QUERY WITH GROUP BY AND ORDER BY CLAUSES INCLUDES AN UNNECESSARY SORT
For the following query the access path includes a sort although it is not necessary: 2017-04-20

13.    PI69349: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query    2017-04-14

14.    PI74019: DEFECT 40316 - TPCD (REVISTIT) QUERY #UV1B2 CL2 CPU REGRESSION IN V12
There is a regression for performance test. In V11, it could choose good access path, in V12, it chooses bad access path.   2017-04-03

15.    PI72887: INEFFICIENT ACCESS PATH WITH EARLY OUT
INEFFICIENT ACCESS PATH WITH EARLY OUT 2017-04-03

16.    PI71495: ABEND04E RC00E70005 AT DSNXGRDS DSNXOB2 M105 ON SQL STATEMENT WITH CONCENTRATE STATEMENTS WITH LITERALS
ABEND04E rc00e70005 at dsnxgrds dsnxob2 M105 in prepare SQL statement with attributes clause CONCENTRATE STATEMENTS WITH       2017-02-01

17.    PI72800: INCORRECT FILTER FACTOR FOR PARTITION KEY OF VOLATILE TABLE
Db2 may calculate a incorrect filter factor for using BETWEEN and RANGE predicates, when a volatile table is defined as 2017-02-01

18.    PI71110: FORWARDFIT OF PI70237
Performance problem when a user query choose R-scan in a single-table correlated subquery.    2017-02-01

19.    PI68238: SQLACCESSPATH OF THE ENTRY WITH LATEST TIMESTAMP AND ACCESSTYPE NR IS NOT SELECTED WHEN BIND PKG WITH OPTHINT ...
When BIND PACKAGE with OPTHINT and EXPLAIN(YES), the latest timestamp NR path will lost the chance to compete with other 2017-01-12

20.    PI68551: FF OF PI66289-INDEX WITH LESS MATCHING COLUMNS IS CHOSEN FOR INNER TABLE WHICH MAY CAUSE BAD PERFORMANCE
Index with less matching columns is chosen for inner table which may cause bad performance    2017-01-12

21.    PI69414: POOR SQL PERFORMANCE FOR MERGE STATEMENT
Poor SQL performance for MERGE statement       2017-01-03

22.    PI68086: ALLOW MORE TABLES TO BE ELIGIBLE FOR SPARSE INDEX ACCESS.
Due to a code bug, sometimes a table with very big non-correlated subquery (big means expensive in terms of elapsed    2016-12-01

 

Remove the filter for optimizer csects and you get 26:


1.     PI82797: LESS FILTERING INDEX SELECTED FOR INNER TABLE OF NESTED LOOP JOIN
A smaller, less filtering index is selected for the inner table with a Nested Loop Join.      2017-10-02

2.     PI78122: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-10-02

3.     PI83289: QUERY ACCESS PATH MAY BE UNPREDICTABLE FOR A QUERY WHERE THERE ARE EQUAL PREDICATES COVERING ALL THE COLUMNS ...
Query access path may be unpredictable for a query where there are equal predicates covering all the columns of a unique index.        2017-09-02

4.     PI83454: INEFFICIENT ACCESS PATH IS USED BECAUSE OF AN INCORRECT COMPOUND FILTER FACTOR OF RANGE PREDICATES
The compound filter factor of two range predicates on the same column is underestimated, that causes an inefficient access      2017-09-02

5.     PI83547: NON-MATCHING INDEX CHOSEN WHEN A MATCHING INDEX EXISTS
A non-matching index could be chosen when an index with good matching exists.    2017-09-02

6.     PI82634: MULTI INDEX ACCESS CHOSEN WHEN A BETTER MATCHING INDEX EXISTS
MULTI-INDEX ACCESS WAS CHOSEN WHEN A MORE EFFICIENT INDEX USING BETTER MATCHING EXISTS.       2017-08-02

7.     PI77792: ABSTRACT:INEFFICIENT ACCESS PATH WITH SORT DISTINCT IN CTE
AN INEFFICIENT ACCESS PATH CAN BE CHOSEN WHEN A SORT FOR DISTINCT IS NEEDED INSIDE A CTE.     2017-06-02

8.     PI73290: Db2 FOR Z/OS USERS OF QUERIES WITH GROUP BY, DISTINCT, IN SUBQUERY OR NOT IN SUBQUERY.
Db2 may choose an inefficient access path as non-matching index access without matching predicates and screening predicates when     2017-05-01

9.     PI75966: INEFFICIENT ACCESS PATH IS SELECTED.
List prefetch plan with higher cost may be chosen mistakenly when there is one table in the query block and the index covers        2017-05-01

10.    PI73368: ABSTRACT=INEFFICIENT ACCESS PATH WITH SINGLE VALUE PAGE RANGE PREDICATE.
An inefficient access path can be chosen when page range access is used for a join predicate and the columns has a cardinality 2017-05-01

11.    PI71368: R-SCAN ACCESS PATH CHOSEN OVER MULTI-INDEX ACCESS FOR A TABLE WHICH QUALIFIES FOR NPGTHRSH BEHAVIOR
R-scan access path chosen over multi-index access for a table which qualifies for NPGTHRSH behavior.        2017-04-20

12.    PI75963: ACCESS PATH FOR A QUERY WITH GROUP BY AND ORDER BY CLAUSES INCLUDES AN UNNECESSARY SORT
For the following query the access path includes a sort although it is not necessary: 2017-04-20

13.    PI67390: SQLCODE100 MAY OCCUR FOR SQL STATEMENTS USING LIST PREFETCH OR MULTI INDEX ACCESS
SQLCODE +100 may occur for sql statements using List Prefetch or multi index access    2017-04-14

14.    PI69349: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query    2017-04-14

15.    PI69054: TOTALENTRIES TRUNCATED IN RTS FOR LARGE LOAD RESULTS IN REBUILD INDEX FAILING
2.6 billion row table load is truncating totalentries in RTS.      2017-04-12

16.    PI74019: DEFECT 40316 - TPCD (REVISTIT) QUERY #UV1B2 CL2 CPU REGRESSION IN V12
There is a regression for performance test. In V11, it could choose good access path, in V12, it chooses bad access path.   2017-04-03

17.    PI76121: REMOTE CONNECTION ATTEMPT RESULTS IN NONMATCHING INDEX SCAN OF DSNFEX01 WHEN ROW FOR AUTHID IS MISSING FROM ...
Db2DDF See APAR PI71693 for Db2 11/10 for z/OS.       2017-04-03

18.    PI72887: INEFFICIENT ACCESS PATH WITH EARLY OUT
INEFFICIENT ACCESS PATH WITH EARLY OUT 2017-04-03

19.    PI71495: ABEND04E RC00E70005 AT DSNXGRDS DSNXOB2 M105 ON SQL STATEMENT WITH CONCENTRATE STATEMENTS WITH LITERALS
ABEND04E rc00e70005 at dsnxgrds dsnxob2 M105 in prepare SQL statement with attributes clause CONCENTRATE STATEMENTS WITH       2017-02-01

20.    PI72800: INCORRECT FILTER FACTOR FOR PARTITION KEY OF VOLATILE TABLE
Db2 may calculate a incorrect filter factor for using BETWEEN and RANGE predicates, when a volatile table is defined as 2017-02-01

21.    PI71110: FORWARDFIT OF PI70237
Performance problem when a user query choose R-scan in a single-table correlated subquery.    2017-02-01

22.    PI68238: SQLACCESSPATH OF THE ENTRY WITH LATEST TIMESTAMP AND ACCESSTYPE NR IS NOT SELECTED WHEN BIND PKG WITH OPTHINT ...
When BIND PACKAGE with OPTHINT and EXPLAIN(YES), the latest timestamp NR path will lost the chance to compete with other 2017-01-12

23.    PI68551: FF OF PI66289-INDEX WITH LESS MATCHING COLUMNS IS CHOSEN FOR INNER TABLE WHICH MAY CAUSE BAD PERFORMANCE
Index with less matching columns is chosen for inner table which may cause bad performance    2017-01-12

24.    PI69414: POOR SQL PERFORMANCE FOR MERGE STATEMENT
Poor SQL performance for MERGE statement       2017-01-03

25.    PI68086: ALLOW MORE TABLES TO BE ELIGIBLE FOR SPARSE INDEX ACCESS.
Due to a code bug, sometimes a table with very big non-correlated subquery (big means expensive in terms of elapsed    2016-12-01

26.    PI69029: REBIND APREUSESOURCE(PREVIOUS) IS NOT FINDING PREVIOUS ACCESSPATH WHEN USING PLANMGMT(BASIC)
When running this sample statement: REBIND PACKAGE(TEST.ABC00999.()) EXPLAIN(Y) -      2016-12-01

 

So we are talking about just over two per month…

 

Db2 11 APAR Review sqlaccesspath

Just drop the C10 and add B10 to the search and do it all again.


1.     PI78532: NON-MATCHING INDEX CHOSEN WHEN A MATCHING INDEX EXISTS 17/08/30 PTF PECHANGE
A non-matching index could be chosen when an index with good matching exists. 2017-08-30

2.     PI58411: INCORROUT CAN OCCUR FOR AN UPDATE QUERY USING TEMPORAL TABLES.
Temporal table has multiple indexes. One index to support the primary key constraint and one to support queries against the       2017-01-04

3.     PI62713: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query with LEFT OUTER JOIN and ORDER BY and also running with Sort     2016-11-02

4.     PI64779: SELECT DISTINCT RETURNS DUPLICATE VALUES.
Incorrect output can occur when the DISTINCT keyword is used, matching index access is used on the IN-list, but the IN-list   2016-10-03

5.     PI61893: INCORROUT WITH UPDATE STATEMENT AND CORRELATED SUBQUERY
A INCORROUT conditions occurs when a UPDATE statement is coded with a correlated subquery that contains a DISTINCT and FETCH     2016-08-02

 

Again, remove the yesHIPER and now there are 54:


1.     PI79438: INEFFICIENT ACCESS PATH FOR QUERY WITH MIN/MAX AND NO GROUP BY
An inefficient access path can be chosen when a query contains a MIN/MAX function with no Group BY.        2017-10-02

2.     PI84286: JOIN PREDICATE WITH CAST FUNCTION NON-INDEXABLE
A join predicate can become non-indexable if the predicate contains a decimal function without the length and scale    2017-10-02

3.     PI83769: AN INEFFICIENT INDEX CAN BE SELECTED TO PARTICIPATE IN MULTI-INDEX ACCESS
AN INEFFICIENT INDEX CAN BE SELECTED TO PARTICIPATE IN MULTI-INDEX ACCESS WHEN THERE IS A HIGH DEGREE OF UNCERTAINTY      2017-09-26

4.     PI82601: LESS FILTERING INDEX SELECTED FOR INNER TABLE OF NESTED LOOP JOIN
A smaller, less filtering index is selected for the inner table with a Nested Loop Join.      2017-09-02

5.     PI82772: INEFFICIENT ACCESS PATH IS USED BECAUSE OF AN INCORRECT COMPOUND FILTER FACTOR OF RANGE PREDICATES
The compound filter factor of two range predicates on the same column is underestimated, that causes an inefficient access      2017-09-02

6.     PI63607: INEFFICIENT ACCESS PATH COULD OCCUR WITH CARTESIAN JOIN
An inefficient access path could occur when the result of a Cartesian join does not produce better index matching on the      2017-08-30

7.     PI78532: NON-MATCHING INDEX CHOSEN WHEN A MATCHING INDEX EXISTS 17/08/30 PTF PECHANGE
A non-matching index could be chosen when an index with good matching exists.    2017-08-30

8.     PI79775: INDEX PROBING NOT BEING INVOKED
Under certain conditions, index probing is not being utilized for predicates that calculate a FF with no matching rows    2017-08-02

9.     PI80690: AE PI76369 FIX COMPLETION
AE PI76369 fix completion.        2017-07-05

10.    PI76369: ABSTRACT:INEFFICIENT ACCESS PATH WITH SORT DISTINCT IN CTE
AN INEFFICIENT ACCESS PATH CAN BE CHOSEN WHEN A SORT FOR DISTINCT IS NEEDED INSIDE A CTE.     2017-06-05

11.    PI75212: DURING AUTOBIND USING QUERYACCELERATION (ENABLE) BIND OPTION, STATIC QUERY IS BOUND FOR ACCELERATION ...
During AUTOBIND for a package bound QUERYACCELERATION(ENABLE), Db2 unexpectedly selects an IDAA access path and binds the query   2017-06-02

12.    PI59793: UNDERESTIMATED TOTAL INDEX FILTERING WITH PAGE RANGE SCREENING WHEN THE PAGE RANGE COLUMNS ARE NOT IN THE INDEX
An inaccurate IMFFADJ value will be generated in instances where when page range screening is performed and the columns used for      2017-05-03

13.    PI62376: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-04-11

14.    PI75342: ACCESS PATH FOR A QUERY WITH GROUP BY AND ORDER BY CLAUSES INCLUDES AN UNNECESSARY SORT.
For the following query the access path includes a sort although it is not necessary: 2017-04-03

15.    PI72177: INEFFICIENT ACCESS PATH IS SELECTED.
List prefetch plan with higher cost may be chosen mistakenly when there is one table in the query block and the index covers        2017-04-03

16.    PI70394: ABSTRACT=INEFFICIENT ACCESS PATH WITH SINGLE VALUE PAGE RANGE PREDICATE.
An inefficient access path can be chosen when page range access is used for a join predicate and the columns has a cardinality 2017-03-09

17.    PI73338: INEFFICIENT JOIN ACCESS ON PARTITIONED TABLE
Nested loop join may be chosen as the join type when hybrid join would likely have been a better choice.      2017-02-01

18.    PI66289: INDEX WITH LESS MATCHING COLUMNS IS CHOSEN FOR INNER TABLE WHICH MAY CAUSE BAD PERFORMANCE
Index with less matching columns is chosen for inner table which may cause bad performance    2017-01-12

19.    PI65041: SQLACCESSPATH OF THE ENTRY WITH LATEST TIMESTAMP AND ACCESSTYPE NR IS NOT SELECTED WHEN BIND PKG WITH OPTHINT ...
When BIND PACKAGE with OPTHINT and EXPLAIN(YES), the latest timestamp NR path will lost the chance to compete with other 2017-01-12

20.    PI58411: INCORROUT CAN OCCUR FOR AN UPDATE QUERY USING TEMPORAL TABLES.
Temporal table has multiple indexes. One index to support the primary key constraint and one to support queries against the       2017-01-04

21.    PI69685: ABEND04E RC00E70005 AT DSNXGRDS DSNXOB2 M105 ON AN SQL STATEMENT WITH ATTRIBUTE CONCENTRATE STATEMENTS WITH ...
ABEND04E rc00e70005 at dsnxgrds dsnxob2 M105 in a prepared SQL statement with prepared attributes clause CONCENTRATE STATEMENTS     2017-01-03

22.    PI71365: R-SCAN ACCESS PATH CHOSEN OVER MULTI-INDEX ACCESS FOR A TABLE WHICH QUALIFIES FOR NPGTHRSH BEHAVIOR
R-scan access path chosen over multi-index access for a table which qualifies for NPGTHRSH behavior.        2017-01-03

23.    PI68896: INCORRECT FILTER FACTOR FOR PARTITION KEY OF VOLATILE TABLE
Db2 may calculate a incorrect filter factor for using BETWEEN and RANGE predicates, when a volatile table is defined as 2017-01-03

24.    PI71415: POOR SQL PERFORMANCE WHEN THE ACCESS PATH USES NON-MATCHING INDEX FOR INDEX SKIPPING
Poor SQL Performance when the access path uses non-matching index for index skipping . 2017-01-03

25.    PI63541: INEFFICIENT ACCESS PATH WITH EARLY OUT
Ineffecient access path can be chosen when the access plan qualifies for index skipping but no index covers the join     2017-01-03

26.    PI68380: SUBOPTIMAL ACCESS PATH WITH A NESTED LOOP JOIN AND MULTI-INDEX ACCESS
A suboptimal access path is chosen when multi-index access is chosen as the inner table for a nested loop join. A hybrid join   2016-12-01

27.    PI67499: INEFFICIENT NON-MATCHING INDEX SCAN IS SELECTED WHEN THERE ARE MORE THAN 1 TABLES IN THE QUERY BLOCK WITH ...
Inefficient non-matching index scan is selected when when the query contains DISTINCT in the query and there are more than 1 2016-12-01

28.    PI70237: INEFFICIENT ACCESS PATH WHEN A QUERY HAS INSUBQ OR EXISTS-SUBQ AND THE SUBQUERY HAS A SINGLE TABLE
Inefficient access path when a query has INSUBQUERY or EXISTS-SUBQUERY and the subquery has a single table. Optimizer    2016-12-01

29.    PI66248: INEFFICIENT ACCESS PATH WHEN NESTED LOOP JOIN USED TO ACCESS A INNER MATERIALIZED QUERY BLOCK
An inefficient rscan access path for the inner table of a nested loop join when the the inner table is a materialized workfile.       2016-12-01

30.    PI64874: INDEX PROBING MAY ACCESS UNQUALIFIED PARTITION AT PREPARE TIME
Unqualified partitions are claimed by index probing at prepare time, that causes unnecessary locking issue and group buffer     2016-11-02

31.    PI62713: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query with LEFT OUTER JOIN and ORDER BY and also running with Sort     2016-11-02

32.    PI52204: INCORRECT DPSI LEAF PAGE ESTIMATION WHEN ALL THE PARTITION KEYS CONTAINS LOCAL PREDICATES
Inefficient access path is selected due to incorrect DPSI leaf page estimation when all the partition keys contains local 2016-10-03

33.    PI64779: SELECT DISTINCT RETURNS DUPLICATE VALUES.
Incorrect output can occur when the DISTINCT keyword is used, matching index access is used on the IN-list, but the IN-list   2016-10-03

34.    PI64234: INEFFICIENT ACCESS PATH INVOLVING RANGE LIST PREDICATE(S)
A Range list access path could be chosen when a more efficient access path is available.      2016-10-03

35.    PI64089: PERFORMANCE IMPACT WITH CTE SELECTED FROM A VIEW
When a CTE is defined in a view, a sub-optimal access path may occur. A optimal access path will be estimated for the CTE, and        2016-10-03

36.    PI61435: INCORRECT FILTER FACTOR MAY BE ASSIGNED FOR PAGE RANGE SCREENING PREDICATES WHEN PARTITION KEYS ARE DEFINED AS ...
Incorrect filter factor may be assigned for page range screening predicates when partition keys are defined as VARCHAR 2016-10-03

37.    PI60761: Enable NPGTHRSH for qualified partitions of a partitioned table based on partition level NPAGES.
The code to enable NPGTHRSH for qualified partitions of a partitioned table based on partition level stats (NPAGES)      2016-09-02

38.    PI61886: IN SUBQUERY FAILS TO MATCH ON INDEXABLE IN LIST COLUMN
For a query which contains an IN list on a subquery, Db2 currently will use the IN list column in an index match if the 2016-09-02

39.    PI60056: INEFFICIENT ACCESS PATH WITH AGGREGATE FUNCTIONS SELECT(MAX) OR SELECT(MIN).
Less than optimal performance is the result when the optimizer makes a inefficient access path decision when the aggregate       2016-08-02

40.    PI60333: UNNECESSARY SORT FOR ORDER BY WHEN DISTINCT/GROUP BY LIST COVERS A UNIQUE INDEX AND SELECTED INDEX SUPPORT ...
When a query contains an ORDER BY and DISTINCT/GROUP BY clause whose columns cover a unique index, Db2 selects an index with 2016-08-02

41.    PI61893: INCORROUT WITH UPDATE STATEMENT AND CORRELATED SUBQUERY
A INCORROUT conditions occurs when a UPDATE statement is coded with a correlated subquery that contains a DISTINCT and FETCH     2016-08-02

42.    PI60206: POOR SQL PERFORMANCE OF A QUERY THAT HAS A CORRELATED SUBQUERY COST REDUCTION
Poor SQL performance of a query that has a correlated subquery cost reduction . 2016-08-02

43.    PI59348: INEFFICIENT INDEX SELECTION FOR THE INNER TABLE OF A JOIN
Less than optimal performance is the result when the optimizer makes a inefficient index selection for the inner table of a   2016-07-15

44.    PI57513: GROUP BY/DISTINCT/MIN/MAX CLAUSES RESULT IN INCORRECT ACCESS PATH DUE TO INVALID COST REDUCTION
In V11, materialized work files which are used as the inner tables for left joins are being processed using a nested loop 2016-07-04

45.    PI61155: INCORRECT COMPOUND FILTER FACTOR ESTIMATION FOR TWO RANGE PREDICATES
Inefficient index is selected due to incorrect compound filter factor estimation for two range predicates. 2016-07-04

46.    PI50999: INCORRECT MATCHING FILTER FACTOR ESTIMATION FOR DPSI WHEN THE JOIN PREDICATES INVOLVE PARTITION KEY
Inefficient access path is used in a join or correlated subquery because IMFF of DPSI is not correctly estimated when the join       2016-06-02

47.    PI58329: INCORRECT VALUE IN QW0022RX FIELD FOR IFCID022 WHEN UNDER REOPT(ONCE) OR REOPT(AUTO)
Incorrect value in QW0022RX field for IFCID022 when under REOPT ONCE OR REOPT AUTO .   2016-05-04

48.    PI53774: INEFFICIENT ACCESS PATH CHOSEN WHEN Db2 INCORRECTLY ESTIMATES THE FILTERING WHEN COMBINING TWO RANGE ...
Inefficient access path may be chosen when Db2 incorrectly estimates the filtering when combining two range predicates into      2016-04-05

49.    PI54988: OPTIMAL INDEX ACCESS MAY NOT BE USED WHEN STATISTICS IS NOT COLLECTED
Optimal index access may not be used when statistics is not collected.    2016-04-05

50.    PI44963: INCORRECT COST ESTIMATION FOR I1 INDEX SCAN
Cost estimation in DSN_STATEMNT_TABLE is very high for one-fetch index scan(I1). Prefetch method is 'D' in the   2016-03-10

51.    PI53790: INCORRECT ACCESS PATH CHOSEN FOR OPTIMIZE FOR 1 ROW
Db2 is producing an incorrect and inefficient access path in V11 when the OPTIMIZE FOR 1 ROW clause is added to a query which 2016-03-02

52.    PI50063: AN INACCURATE COMPOUND FILTER FACTOR MAY BE PRODUCED FOR A PREDICATE WITH AN OR CLAUSE
AN INACCURATE COMPOUND FILTER FACTOR MAY BE PRODUCED FOR A PREDICATE WITH AN OR CLAUSE 2016-02-01

53.    PI49507: DIFFERENT ACCESS PATH IS USED WHEN QUERY ON VIEW INSTEAD OF BASE TABLE.
A view is directly created on a base table. SQL statement on the view should be equivalent to the SQL on the base table. 2016-02-01

54.    PI49557: INEFFICIENT ACCESS PATH FOR QUERY WITH FUNCTION MIN OR MAX BY INCORRECT REDUCTION FOR EARLY OUT
Inefficient access path for query with function MIN or MAX by incorrect reduction for early out        2016-01-04

 

Remove the filter for optimizer csects and you get 56:


1.     PI79438: INEFFICIENT ACCESS PATH FOR QUERY WITH MIN/MAX AND NO GROUP BY
An inefficient access path can be chosen when a query contains a MIN/MAX function with no Group BY.        2017-10-02

2.     PI84286: JOIN PREDICATE WITH CAST FUNCTION NON-INDEXABLE
A join predicate can become non-indexable if the predicate contains a decimal function without the length and scale    2017-10-02

3.     PI83769: AN INEFFICIENT INDEX CAN BE SELECTED TO PARTICIPATE IN MULTI-INDEX ACCESS
AN INEFFICIENT INDEX CAN BE SELECTED TO PARTICIPATE IN MULTI-INDEX ACCESS WHEN THERE IS A HIGH DEGREE OF UNCERTAINTY      2017-09-26

4.     PI86573: BETTER MATCHING INDEX NOT CHOSEN WHEN COMPETING INDEXES CONTAIN A SUBSET OF THE SAME COLUMNS.
A better matching index can be overlooked when the competing indexes share a set of the same columns.        2017-09-21

5.     PI82772: INEFFICIENT ACCESS PATH IS USED BECAUSE OF AN INCORRECT COMPOUND FILTER FACTOR OF RANGE PREDICATES
The compound filter factor of two range predicates on the same column is underestimated, that causes an inefficient access      2017-09-02

6.     PI82601: LESS FILTERING INDEX SELECTED FOR INNER TABLE OF NESTED LOOP JOIN
A smaller, less filtering index is selected for the inner table with a Nested Loop Join.      2017-09-02

7.     PI78532: NON-MATCHING INDEX CHOSEN WHEN A MATCHING INDEX EXISTS 17/08/30 PTF PECHANGE
A non-matching index could be chosen when an index with good matching exists.    2017-08-30

8.     PI63607: INEFFICIENT ACCESS PATH COULD OCCUR WITH CARTESIAN JOIN
An inefficient access path could occur when the result of a Cartesian join does not produce better index matching on the      2017-08-30

9.     PI79775: INDEX PROBING NOT BEING INVOKED
Under certain conditions, index probing is not being utilized for predicates that calculate a FF with no matching rows    2017-08-02

10.    PI80690: AE PI76369 FIX COMPLETION
AE PI76369 fix completion.        2017-07-05

11.    PI76369: ABSTRACT:INEFFICIENT ACCESS PATH WITH SORT DISTINCT IN CTE
AN INEFFICIENT ACCESS PATH CAN BE CHOSEN WHEN A SORT FOR DISTINCT IS NEEDED INSIDE A CTE.     2017-06-05

12.    PI75212: DURING AUTOBIND USING QUERYACCELERATION (ENABLE) BIND OPTION, STATIC QUERY IS BOUND FOR ACCELERATION ...
During AUTOBIND for a package bound QUERYACCELERATION(ENABLE), Db2 unexpectedly selects an IDAA access path and binds the query   2017-06-02

13.    PI59793: UNDERESTIMATED TOTAL INDEX FILTERING WITH PAGE RANGE SCREENING WHEN THE PAGE RANGE COLUMNS ARE NOT IN THE INDEX
An inaccurate IMFFADJ value will be generated in instances where when page range screening is performed and the columns used for      2017-05-03

14.    PI62376: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-04-11

15.    PI75342: ACCESS PATH FOR A QUERY WITH GROUP BY AND ORDER BY CLAUSES INCLUDES AN UNNECESSARY SORT.
For the following query the access path includes a sort although it is not necessary: 2017-04-03

16.    PI72177: INEFFICIENT ACCESS PATH IS SELECTED.
List prefetch plan with higher cost may be chosen mistakenly when there is one table in the query block and the index covers        2017-04-03

17.    PI70394: ABSTRACT=INEFFICIENT ACCESS PATH WITH SINGLE VALUE PAGE RANGE PREDICATE.
An inefficient access path can be chosen when page range access is used for a join predicate and the columns has a cardinality 2017-03-09

18.    PI73338: INEFFICIENT JOIN ACCESS ON PARTITIONED TABLE
Nested loop join may be chosen as the join type when hybrid join would likely have been a better choice.      2017-02-01

19.    PI66289: INDEX WITH LESS MATCHING COLUMNS IS CHOSEN FOR INNER TABLE WHICH MAY CAUSE BAD PERFORMANCE
Index with less matching columns is chosen for inner table which may cause bad performance    2017-01-12

20.    PI65041: SQLACCESSPATH OF THE ENTRY WITH LATEST TIMESTAMP AND ACCESSTYPE NR IS NOT SELECTED WHEN BIND PKG WITH OPTHINT ...
When BIND PACKAGE with OPTHINT and EXPLAIN(YES), the latest timestamp NR path will lost the chance to compete with other 2017-01-12

21.    PI58411: INCORROUT CAN OCCUR FOR AN UPDATE QUERY USING TEMPORAL TABLES.
Temporal table has multiple indexes. One index to support the primary key constraint and one to support queries against the       2017-01-04

22.    PI69685: ABEND04E RC00E70005 AT DSNXGRDS DSNXOB2 M105 ON AN SQL STATEMENT WITH ATTRIBUTE CONCENTRATE STATEMENTS WITH ...
ABEND04E rc00e70005 at dsnxgrds dsnxob2 M105 in a prepared SQL statement with prepared attributes clause CONCENTRATE STATEMENTS     2017-01-03

23.    PI71365: R-SCAN ACCESS PATH CHOSEN OVER MULTI-INDEX ACCESS FOR A TABLE WHICH QUALIFIES FOR NPGTHRSH BEHAVIOR
R-scan access path chosen over multi-index access for a table which qualifies for NPGTHRSH behavior.        2017-01-03

24.    PI68896: INCORRECT FILTER FACTOR FOR PARTITION KEY OF VOLATILE TABLE
Db2 may calculate a incorrect filter factor for using BETWEEN and RANGE predicates, when a volatile table is defined as 2017-01-03

25.    PI71415: POOR SQL PERFORMANCE WHEN THE ACCESS PATH USES NON-MATCHING INDEX FOR INDEX SKIPPING
Poor SQL Performance when the access path uses non-matching index for index skipping . 2017-01-03

26.    PI63541: INEFFICIENT ACCESS PATH WITH EARLY OUT
Ineffecient access path can be chosen when the access plan qualifies for index skipping but no index covers the join     2017-01-03

27.    PI68380: SUBOPTIMAL ACCESS PATH WITH A NESTED LOOP JOIN AND MULTI-INDEX ACCESS
A suboptimal access path is chosen when multi-index access is chosen as the inner table for a nested loop join. A hybrid join   2016-12-01

28.    PI67499: INEFFICIENT NON-MATCHING INDEX SCAN IS SELECTED WHEN THERE ARE MORE THAN 1 TABLES IN THE QUERY BLOCK WITH ...
Inefficient non-matching index scan is selected when when the query contains DISTINCT in the query and there are more than 1 2016-12-01

29.    PI70237: INEFFICIENT ACCESS PATH WHEN A QUERY HAS INSUBQ OR EXISTS-SUBQ AND THE SUBQUERY HAS A SINGLE TABLE
Inefficient access path when a query has INSUBQUERY or EXISTS-SUBQUERY and the subquery has a single table. Optimizer    2016-12-01

30.    PI66248: INEFFICIENT ACCESS PATH WHEN NESTED LOOP JOIN USED TO ACCESS A INNER MATERIALIZED QUERY BLOCK
An inefficient rscan access path for the inner table of a nested loop join when the the inner table is a materialized workfile.       2016-12-01

31.    PI64874: INDEX PROBING MAY ACCESS UNQUALIFIED PARTITION AT PREPARE TIME
Unqualified partitions are claimed by index probing at prepare time, that causes unnecessary locking issue and group buffer     2016-11-02

32.    PI62713: INCORROUT WITH SQLSTATE 01003 OCCURRED FOR A QUERY WITH LEFT OUTER JOIN AND ORDER BY AND ALSO RUNNING WITH ...
incorrout (wrong data) with SQLSTATE 01003 occurred for a query with LEFT OUTER JOIN and ORDER BY and also running with Sort     2016-11-02

33.    PI52204: INCORRECT DPSI LEAF PAGE ESTIMATION WHEN ALL THE PARTITION KEYS CONTAINS LOCAL PREDICATES
Inefficient access path is selected due to incorrect DPSI leaf page estimation when all the partition keys contains local 2016-10-03

34.    PI64234: INEFFICIENT ACCESS PATH INVOLVING RANGE LIST PREDICATE(S)
A Range list access path could be chosen when a more efficient access path is available.      2016-10-03

35.    PI64779: SELECT DISTINCT RETURNS DUPLICATE VALUES.
Incorrect output can occur when the DISTINCT keyword is used, matching index access is used on the IN-list, but the IN-list   2016-10-03

36.    PI64089: PERFORMANCE IMPACT WITH CTE SELECTED FROM A VIEW
When a CTE is defined in a view, a sub-optimal access path may occur. A optimal access path will be estimated for the CTE, and        2016-10-03

37.    PI61435: INCORRECT FILTER FACTOR MAY BE ASSIGNED FOR PAGE RANGE SCREENING PREDICATES WHEN PARTITION KEYS ARE DEFINED AS ...
Incorrect filter factor may be assigned for page range screening predicates when partition keys are defined as VARCHAR 2016-10-03

38.    PI60761: Enable NPGTHRSH for qualified partitions of a partitioned table based on partition level NPAGES.
The code to enable NPGTHRSH for qualified partitions of a partitioned table based on partition level stats (NPAGES)      2016-09-02

39.    PI61886: IN SUBQUERY FAILS TO MATCH ON INDEXABLE IN LIST COLUMN
For a query which contains an IN list on a subquery, Db2 currently will use the IN list column in an index match if the 2016-09-02

40.    PI60056: INEFFICIENT ACCESS PATH WITH AGGREGATE FUNCTIONS SELECT(MAX) OR SELECT(MIN).
Less than optimal performance is the result when the optimizer makes a inefficient access path decision when the aggregate       2016-08-02

41.    PI60333: UNNECESSARY SORT FOR ORDER BY WHEN DISTINCT/GROUP BY LIST COVERS A UNIQUE INDEX AND SELECTED INDEX SUPPORT ...
When a query contains an ORDER BY and DISTINCT/GROUP BY clause whose columns cover a unique index, Db2 selects an index with 2016-08-02

42.    PI61893: INCORROUT WITH UPDATE STATEMENT AND CORRELATED SUBQUERY
A INCORROUT conditions occurs when a UPDATE statement is coded with a correlated subquery that contains a DISTINCT and FETCH     2016-08-02

43.    PI60206: POOR SQL PERFORMANCE OF A QUERY THAT HAS A CORRELATED SUBQUERY COST REDUCTION
Poor SQL performance of a query that has a correlated subquery cost reduction . 2016-08-02

44.    PI59348: INEFFICIENT INDEX SELECTION FOR THE INNER TABLE OF A JOIN
Less than optimal performance is the result when the optimizer makes a inefficient index selection for the inner table of a   2016-07-15

45.    PI54868: PERFORMANCE DEGRADATION WITH PAGE RANGE FILTERING ON A JOIN PREDICATE AND NO LOCAL PREDICATES
Db2 is not estimating the correct index filtering when page range filtering is available on a join predicate and no local     2016-07-12

46.    PI57513: GROUP BY/DISTINCT/MIN/MAX CLAUSES RESULT IN INCORRECT ACCESS PATH DUE TO INVALID COST REDUCTION
In V11, materialized work files which are used as the inner tables for left joins are being processed using a nested loop 2016-07-04

47.    PI61155: INCORRECT COMPOUND FILTER FACTOR ESTIMATION FOR TWO RANGE PREDICATES
Inefficient index is selected due to incorrect compound filter factor estimation for two range predicates. 2016-07-04

48.    PI50999: INCORRECT MATCHING FILTER FACTOR ESTIMATION FOR DPSI WHEN THE JOIN PREDICATES INVOLVE PARTITION KEY
Inefficient access path is used in a join or correlated subquery because IMFF of DPSI is not correctly estimated when the join       2016-06-02

49.    PI58329: INCORRECT VALUE IN QW0022RX FIELD FOR IFCID022 WHEN UNDER REOPT(ONCE) OR REOPT(AUTO)
Incorrect value in QW0022RX field for IFCID022 when under REOPT ONCE OR REOPT AUTO .   2016-05-04

50.    PI53774: INEFFICIENT ACCESS PATH CHOSEN WHEN Db2 INCORRECTLY ESTIMATES THE FILTERING WHEN COMBINING TWO RANGE ...
Inefficient access path may be chosen when Db2 incorrectly estimates the filtering when combining two range predicates into      2016-04-05

51.    PI54988: OPTIMAL INDEX ACCESS MAY NOT BE USED WHEN STATISTICS IS NOT COLLECTED
Optimal index access may not be used when statistics is not collected.    2016-04-05

52.    PI44963: INCORRECT COST ESTIMATION FOR I1 INDEX SCAN
Cost estimation in DSN_STATEMNT_TABLE is very high for one-fetch index scan(I1). Prefetch method is 'D' in the   2016-03-10

53.    PI53790: INCORRECT ACCESS PATH CHOSEN FOR OPTIMIZE FOR 1 ROW
Db2 is producing an incorrect and inefficient access path in V11 when the OPTIMIZE FOR 1 ROW clause is added to a query which 2016-03-02

54.    PI50063: AN INACCURATE COMPOUND FILTER FACTOR MAY BE PRODUCED FOR A PREDICATE WITH AN OR CLAUSE
AN INACCURATE COMPOUND FILTER FACTOR MAY BE PRODUCED FOR A PREDICATE WITH AN OR CLAUSE 2016-02-01

55.    PI49507: DIFFERENT ACCESS PATH IS USED WHEN QUERY ON VIEW INSTEAD OF BASE TABLE.
A view is directly created on a base table. SQL statement on the view should be equivalent to the SQL on the base table. 2016-02-01

56.    PI49557: INEFFICIENT ACCESS PATH FOR QUERY WITH FUNCTION MIN OR MAX BY INCORRECT REDUCTION FOR EARLY OUT
Inefficient access path for query with function MIN or MAX by incorrect reduction for early out        2016-01-04

 

So we are still talking about just over two per month…

 

Db2 10 APAR Review sqlaccesspath

Just drop the B10 and add A10 to the search and do it all again.


1.     PI49116: TOTALENTRIES TRUNCATED IN RTS FOR LARGE LOAD RESULTS IN REBUILD INDEX FAILING
2.6 billion row table load is truncating totalentries in RTS.                                                         2016-12-01

2.     PI66401: POOR PERF FOR XMLTABLE FUNCTION WITH PREDICATE BEING PUSHED INSIDE XPATH PRODUCES LOOSE HIGH KEY VALUE FOR ...
The XMLTABLE function is producing a loose high key value for MSIKEYP2 when searching for a specific docid.           2016-12-01

3.     PI15740: INCORROUT DUPLICATED RECORDS RETURNED FOR QUERY WITH SQLACCESSPATH OF RANGELIST
The problem can happen when 1) range list access is used,                                                            2016-01-30

Again, remove the yesHIPER and now there are 16 APARs

 


1.     PI85418: PREPARE TAKES LONG TIME AND HIGH CPU IF THE QUERY CONTAINS MANY OR PREDICATES WHICH MAY QUALIFY RANGE LIST ...
A complex query contains many OR predicates that potentially qualifies range list access(ACCESSTYPE=NR), the prepare of the      2017-09-25

2.     PI76372: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-05-01

3.     PI49116: TOTALENTRIES TRUNCATED IN RTS FOR LARGE LOAD RESULTS IN REBUILD INDEX FAILING
2.6 billion row table load is truncating totalentries in RTS.      2016-12-01

4.     PI66135: INEFFICIENT INDEX MAY BE SELECTED
An inefficient index may be chosen by the optimizer when certain levels of uncertainly exist on some predicates. 2016-12-01

5.     PI66401: POOR PERF FOR XMLTABLE FUNCTION WITH PREDICATE BEING PUSHED INSIDE XPATH PRODUCES LOOSE HIGH KEY VALUE FOR ...
The XMLTABLE function is producing a loose high key value for MSIKEYP2 when searching for a specific docid.       2016-12-01

6.     PI58274: Inefficient access path for a query with OPTIMIZE FOR 1 ROW or FETCH FIRST 1 ROW when an inner index matches ...
When the outer composite is guaranteed to be a single row and OPTIMIZE FOR 1 ROW or FETCH FIRST 1 ROW is specified, Db2 is not   2016-07-04

7.     PI59200: AN INDEX WITH LESS MATCHING COLUMN IS USED WHEN QUERY CONTAINS IN LIST PREDICATE
Optimal index may not be used for below query, SELECT * FROM TB1   2016-07-04

8.     PI39053: CLAIM ACQUIRE FOR SET STATEMENTS AGAINST SYSTSTAB RESULTS IN DSNT501I RC00C200EA DURING CATALOG REORG
Claim acquire for SET statements against SYSTSTAB results in DSNT501I RC00C200EA during Db2 CATALOG REORG 2016-05-19

9.     PI54892: DIFFERENT ACCESS PATH IS USED DUE TO A TIMING ISSUE IN OPTIMIZER
Different access path is used due to a timing issue in optimizer. 2016-05-04

10.    PI53633: PERFORMANCE IMPACT WHEN DSNZPARM MAXRBLK IS SET GREATER THAN ACCEPTABLE VALUE
When MAXRBLK is set to a value of 16777216 or higher, the run time evaluation will be incorrect with the threshold       2016-05-04

11.    PI57655: DIRECT ROW ACCESS IS DEFEATED WHEN THE QUERY HAS FFNR
Poor performance due to Direct Row Access through ROWID column being degraded to index/tablespace scan when the query has a 2016-05-04

12.    PI54978: MERGE STATEMENT USES DEFAULT TABLE CARDINALITY WHEN CARDINALITY IS PROVIDED VIA THE "FOR N ROWS" CLAUSE
The merge statement uses the default table cardinality of 10000 when the cardinality is provided via the "FOR n ROWS" clause.   2016-05-04

13.    PI56300: POOR BIND PERFORMANCE MAY OCCUR DUE TO UNNECESSARY ACCESS TO PLAN_TABLE WHEN SET STATEMENT IS APPLIED
Poor bind performance may occur due to unnecessary access to PLAN_TABLE when SET statement is applied.     2016-04-05

14.    PI49018: ACCESS PATH ENHANCEMENT FOR A QUERY CONTAINING A JOIN PREDICATE ON A TABLE WITH DEFAULT COLUMN CARDINALITY ...
Db2 recognizes cases in which an ordered outer table can provide benefit on access to the inner table. When the outer table is    2016-03-02

15.    PI53169: POOR SQL PERFORMANCE WHEN RANGE LIST ACCESS IS USED AND PTF UI22717 IS APPLIED 15/11/25 PTF PECHANGE
Poor SQL performance when range list access is used and PTF UI22717 is applied .       2016-03-02

16.    PI15740: INCORROUT DUPLICATED RECORDS RETURNED FOR QUERY WITH SQLACCESSPATH OF RANGELIST
The problem can happen when 1) range list access is used,   2016-01-30

 

Remove the filter for optimizer csects and you get 17:


1.     PI85418: PREPARE TAKES LONG TIME AND HIGH CPU IF THE QUERY CONTAINS MANY OR PREDICATES WHICH MAY QUALIFY RANGE LIST ...
A complex query contains many OR predicates that potentially qualifies range list access(ACCESSTYPE=NR), the prepare of the      2017-09-25

2.     PI76372: INEFFICIENT ACCESS PATH CHOSEN WHEN NO MATCHING INDEX EXISTS TO SATISFY THE JOIN PREDICATE.
An inefficient access path can be selected for a query with no matching index to cover the join predicate.   2017-05-01

3.     PI71693: REMOTE CONNECTION ATTEMPT RESULTS IN NONMATCHING INDEX SCAN OF DSNFEX01 WHEN ROW FOR AUTHID IS MISSING FROM ...
Db2DDF See APAR PI76121 for Db2 12 for z/OS.   2017-03-02

4.     PI49116: TOTALENTRIES TRUNCATED IN RTS FOR LARGE LOAD RESULTS IN REBUILD INDEX FAILING
2.6 billion row table load is truncating totalentries in RTS.      2016-12-01

5.     PI66135: INEFFICIENT INDEX MAY BE SELECTED
An inefficient index may be chosen by the optimizer when certain levels of uncertainly exist on some predicates. 2016-12-01

6.     PI66401: POOR PERF FOR XMLTABLE FUNCTION WITH PREDICATE BEING PUSHED INSIDE XPATH PRODUCES LOOSE HIGH KEY VALUE FOR ...
The XMLTABLE function is producing a loose high key value for MSIKEYP2 when searching for a specific docid.       2016-12-01

7.     PI58274: Inefficient access path for a query with OPTIMIZE FOR 1 ROW or FETCH FIRST 1 ROW when an inner index matches ...
When the outer composite is guaranteed to be a single row and OPTIMIZE FOR 1 ROW or FETCH FIRST 1 ROW is specified, Db2 is not   2016-07-04

8.     PI59200: AN INDEX WITH LESS MATCHING COLUMN IS USED WHEN QUERY CONTAINS IN LIST PREDICATE
Optimal index may not be used for below query, SELECT * FROM TB1   2016-07-04

9.     PI39053: CLAIM ACQUIRE FOR SET STATEMENTS AGAINST SYSTSTAB RESULTS IN DSNT501I RC00C200EA DURING CATALOG REORG
Claim acquire for SET statements against SYSTSTAB results in DSNT501I RC00C200EA during Db2 CATALOG REORG 2016-05-19

10.    PI54892: DIFFERENT ACCESS PATH IS USED DUE TO A TIMING ISSUE IN OPTIMIZER
Different access path is used due to a timing issue in optimizer. 2016-05-04

11.    PI53633: PERFORMANCE IMPACT WHEN DSNZPARM MAXRBLK IS SET GREATER THAN ACCEPTABLE VALUE
When MAXRBLK is set to a value of 16777216 or higher, the run time evaluation will be incorrect with the threshold       2016-05-04

12.    PI57655: DIRECT ROW ACCESS IS DEFEATED WHEN THE QUERY HAS FFNR
Poor performance due to Direct Row Access through ROWID column being degraded to index/tablespace scan when the query has a 2016-05-04

13.    PI54978: MERGE STATEMENT USES DEFAULT TABLE CARDINALITY WHEN CARDINALITY IS PROVIDED VIA THE "FOR N ROWS" CLAUSE
The merge statement uses the default table cardinality of 10000 when the cardinality is provided via the "FOR n ROWS" clause.   2016-05-04

14.    PI56300: POOR BIND PERFORMANCE MAY OCCUR DUE TO UNNECESSARY ACCESS TO PLAN_TABLE WHEN SET STATEMENT IS APPLIED
Poor bind performance may occur due to unnecessary access to PLAN_TABLE when SET statement is applied.     2016-04-05

15.    PI49018: ACCESS PATH ENHANCEMENT FOR A QUERY CONTAINING A JOIN PREDICATE ON A TABLE WITH DEFAULT COLUMN CARDINALITY ...
Db2 recognizes cases in which an ordered outer table can provide benefit on access to the inner table. When the outer table is    2016-03-02

16.    PI53169: POOR SQL PERFORMANCE WHEN RANGE LIST ACCESS IS USED AND PTF UI22717 IS APPLIED 15/11/25 PTF PECHANGE
Poor SQL performance when range list access is used and PTF UI22717 is applied .       2016-03-02

17.    PI15740: INCORROUT DUPLICATED RECORDS RETURNED FOR QUERY WITH SQLACCESSPATH OF RANGELIST
The problem can happen when 1) range list access is used,   2016-01-30

So we are still talking about just over one per month, which implies that Db2 10 was “more stable” in this area. To be fair, Db2 10 is a lot older (GA date 2010-10-22) than 11 and 12 so I am not surprised that after seven years the bug rate is dropping off!

What does all this mean?

What it means to me, is that just looking at sqlaccesspath shows a pretty high turnover rate that must be tested. There are HIPERs in here that could really hurt, and so applying maintenance, especially now in the Agile Db2 12 world, becomes even more critical to your business.

Are you ready for this?


More about : Db2 12 SQL access paths; Agile, SQL Codes/Catalog/Function Levels


See also our CDDC tool suite: Continuous Delivery – Deployment Check

CDDC Supports fully automated testing of the new Db2 agile delivery:

– BIF/ICI Detection: Checks incompatibilities on FUNCTION LEVEL
– Access Path PreCheck
– Creates quality environments from a production clone
– Capture the entire workload incl. DCL, DDL, commands…


 

As usual, if you have any comments or queries please feel free to drop me a line!

TTFN

Roy Boxwell

 

 

2016-04 DB2 SYSCOPY – Do you know what is in it? Redux

DB2 10, DB2 11 Migration & DB2 Database maintenance

A special query to check and clear out the DB2 Catalog

 

This is a redux of my original Newsletter from February 2013 with additional data at the very end – The reason for this relaunch? Simple – I have had numerous emails about this topic, especially with regard to migrating from DB2 10 to DB2 11, and it is obviously still very important to check and to clear out *before* you start your DB2 migration. So now enjoy the redux version…

 

DB2 Database Maintenance and the DB2 Catalog

If you have written your own DB2 database maintenance programs then you almost certainly run SQL queries against the DB2 Catalog. If you are also checking for Incremental Image Copies (IIC) or Full Image Copies (FIC) then you will probably be using a mix of Real-Time Statistics tables (RTS) and the SYSIBM.SYSCOPY to figure out which type of utility to generate. Further if you are in DB2 10 (any mode! CM8, CM9, or NF) then this newsletter is for you!

 

I had a problem in one of our test centers with a cursor that I noticed was taking a long time to finish and so I went into our Analyze+ tool and extracted the EDM Pool data (this is the new data in DB2 10 NF that is synonymous with the Dynamic Statement Cache counters and statistics) and sorted by Total Elapsed Time descending to get this:

 

Analyze+ for DB2 z/OS ----- EDM Pool (6/12) -------- Stmt 1 from 316 
Command ===>                                         Scroll ===> CSR  
                                                           DB2: QA1B 
Primary cmd: END, SE(tup), Z(oom), L(ocate) 
             total elapse time                 
Line    cmd: Z(oom), A(nalyze), D(ynamic Analyze), E(dit Statement), 
             P(ackage), S(tatement Text)
                                                               
                     Total       Average         Total       Average
     StmtID   Elapsed Time  Elapsed Time      CPU Time      CPU Time
----------- HHHH:MM:SS.ttt HHH:MM:SS.ttt HHH:MM:SS.ttt HHH:MM:SS.ttt
     115967    1:28.107705     29.369235   1:12.151391     24.050464
     114910       8.367834      0.000331      6.779229      0.000268
      79642       7.998559      0.054412      6.346829      0.043176
     114907       5.760045      0.000238      4.378691      0.000181
     115974       5.031890      2.515945      2.937258      1.468629
       5439       4.037261      0.000739      2.685938      0.000492

 

Over one hour total and over 29 minutes average for our small amount of test data set alarm bells ringing – so I drilled down to the SQL:

 

Analyze+ for DB2 z/OS -- View EDM-Pool Statement LINE 00000001 COL 001 080
Command ===>                                             Scroll ===> CSR
                                                         DB2: QA1B
Primary cmd: END
Collection:RTDX0510_PTFTOOL
Package   :M2DBSC09 
Contoken  :194C89620AE53D88  PrecompileTS: 2012-10-29-15.34.40.938230
StmtID    :          115967  StmtNo      :      1223  SectNo:       2
---------------------------------------------------------------------
DECLARE
  SYSCOPY-IC-MODI-9N
CURSOR WITH HOLD FOR 
SELECT                                                                       
  T1.N1 , T1.N2 , T1.N3 , T1.N4 , T1.N5 , T1.N6 , T1.N7 , T1.N8 , T1.N9 
  , T1.N10 , T1.N11 , T1.N12 
FROM (
  SELECT       
    ICTS.DBNAME AS N1
  , ICTS.TSNAME AS N2
  , ICTS.TIMESTAMP AS N3
  , ' ' AS N4
  , ICTS.DSNUM AS N5
 , ICTS.ICTYPE AS N6
 , DAYS ( :WORK-CURRENT-DATE ) - DAYS ( ICTS.TIMESTAMP ) AS N7
 , ICTS.OTYPE AS N8
 , ICTS.DSNAME AS N9
 , ICTS.ICUNIT AS N10
 , ICTS.INSTANCE AS N11
 , ICTS.STYPE AS N12                                                                    
  FROM SYSIBM.SYSCOPY ICTS                                                     
  WHERE ICTS.ICBACKUP IN ( '  ' , 'LB' , 'FC' )                            
  AND  ICTS.OTYPE = 'T' 
  UNION                    
   SELECT                           
    ICIX.DBNAME AS N1
  , CAST ( TABLES.TSNAME AS CHAR ( 8 ) CCSID EBCDIC ) AS N2
  , ICIX.TIMESTAMP AS N3
  , ICIX.TSNAME AS N4
  , ICIX.DSNUM AS N5
  , ICIX.ICTYPE AS N6
  , DAYS ( :WORK-CURRENT-DATE ) - DAYS ( ICIX.TIMESTAMP ) AS N7
  , ICIX.OTYPE AS N8
  , ICIX.DSNAME AS N9
  , ICIXS.ICUNIT AS N10
  , ICIX.INSTANCE AS N11
  , ICIX.STYPE AS N12
   FROM SYSIBM.SYSCOPY ICIX
      , SYSIBM.SYSINDEXES INDEXES
      , SYSIBM.SYSTABLES TABLES           
   WHERE ICIX.ICBACKUP IN ( '  ' , 'LB' , 'FC' )                          
   AND  ICIX.OTYPE = 'I' 
   AND VARCHAR ( ICIX.DBNAME , 24 ) = INDEXES.DBNAME       
   AND VARCHAR ( ICIX.TSNAME , 24 ) = INDEXES.INDEXSPACE 
   AND INDEXES.TBNAME = TABLES.NAME
   AND INDEXES.TBCREATOR = TABLES.CREATOR           
   AND  TABLES.TYPE IN ( 'H' , 'M' , 'P' , 'T' , 'X' ) )    
 AS T1                                                   
 ORDER BY CAST (T1.N1 AS CHAR ( 8 ) CCSID EBCDIC )
        , CAST (T1.N2 AS CHAR ( 8 ) CCSID EBCDIC )
        , N3 DESC 
 FOR FETCH ONLY       
 WITH UR                                                             



 HOSTVARIABLE NAME             NULLABLE  TYPE           LENGTH  SCALE
 ---------------------------  --------  --------------  -----  -----
 WORK-CURRENT-DATE             NO        CHAR              26       
 WORK-CURRENT-DATE             NO        CHAR              26       
******************************** Bottom of Data **********************

 

Ok, ok this SQL is not going to win a beauty contest any day soon but it used to run just fine…so now I explained it:

Analyze+ for DB2 z/OS -- Explain Data (1/6) --------- Entry 1 from 7  
Command ===>                                         Scroll ===> CSR   
EXPLAIN: DYNAMIC     MODE: CATALOG                         DB2: QA1B  
Primary cmd: END, T(Explain Text), V(iolations), R(unstats), 
             P(redicates), S(tatement Text), C(atalog Data),
             M(ode Catalog/History),Z(oom), PR(int Reports), 
             SAVExxx, SHOWxxx
             
Line    cmd: Z(oom), C(osts), I(ndexes of table), S(hort catalog),
             T(able), V(irtual indexes of table), 
             X(IndeX)                               
Collection : RTDX0510_PTFTOOL   Package : M2DBSC09   Stmt :     1223
Version    : - NONE -         
Milliseconds:  77519  Service Units: 220222  Cost Category: B
                                                                                
  QBNO QBTYPE CREATOR  TABLE NAME       MTCH IX METH PRNT TABL PRE  MXO 
  PLNO TABNO  XCREATOR INDEX NAME ACTYP COLS ON OD   QBLK TYPE FTCH PSQ 
  ---- ------ -------- ---------- ----- ---- -- ---- ---- ---- ---- --- 
     1 SELECT R510PTFT T1         R        0 N     0    0 W    S      0 
     1 5 
     1 SELECT                              0 N     3    0 -           0 
     2 0  
     2 UNION                               0       3    1 -           0 
     1 0 
     3 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0 
     1 1         
     4 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0 
     1 2        
     4 NCOSUB SYSIBM   SYSINDEXES I        2 N     1    2 T           0 
     2 3      SYSIBM   DSNDXX02       
     4 NCOSUB SYSIBM   SYSTABLES  I        2 N     1    2 T           0 
     3 4      SYSIBM   DSNDTX01      
  ---- ------ -------- ---------- ----- ---- -- ---- ---- ---- ---- ---

 

This is *after* I had REORGed the SYSCOPY, SYSTSIXS and SYSTSTAB and then run the RUNSTATS on the SYSTSIXS and SYSTSTAB as you cannot do inline RUNSTATS on those two of course!

 

Two tablespace scans against the SYSCOPY is not brilliant of course but in this system we only have 4,000 table spaces and 2,500 indexes… so then I used the Catalog primary command to have another look at the catalog data:

TS   : DSNDB06 .SYSCOPY 
Stats: 2013-02-04-10.49.32.600316 
  Partitions:  0 , Tables: 1 , NACTIVEF: 18.272 pages 
  Type      :  Neither a LOB nor a MEMBER CLUSTER.
  RTS data TOTALROWS : 347.087 , Pages: 18.268
              
Table: SYSIBM.SYSCOPY 
Stats: 2013-02-04-10.49.32.600316
  No. of rows (CARDF): 347.082 , Pages: 18.268 
  Index: SYSIBM.DSNUCH01 
  Stats: 2013-02-04-10.49.32.600316     Type: Type-2 index
    Levels: 3 , Leaf pages: 3.945 
    FIRSTKEYCARDF: 101 , FULLKEYCARDF: 347.082 
    RTS data Levels: 3 , Leaf pages: 3.945 , TOTALENTRIES: 347.087 
    CLUSTERING: Y , CLUSTERED: Y , CLUSTERRATIO = 100,00% 
    DATAREPEATFACTORF: 18.268 
    Indexcolumn  ! Format        ! Dist. Values ! A/D ! NL ! Stats  
    -------------+---------------+--------------+-----+----+-------
    DBNAME       ! CHAR(8)       !          101 ! ASC ! N  ! OK  
    TSNAME       ! CHAR(8)       !          712 ! ASC ! N  ! OK  
    START_RBA    ! CHAR(6)       !       72.398 ! DSC ! N  ! OK  
    TIMESTAMP    ! TIMESTAMP(6)  !      347.082 ! DSC ! N  ! OK  
                                                                               
  Index: SYSIBM.DSNUCX01                                                 
  Stats: 2013-02-04-10.49.32.600316   Type: Type-2 index 
    Levels: 3 , Leaf pages: 509
    FIRSTKEYCARDF: 1.820 , FULLKEYCARDF: 1.820
    RTS data Levels: 3 , Leaf pages: 509 , TOTALENTRIES: 347.087 
    CLUSTERING: N , CLUSTERED: Y , CLUSTERRATIO = 100,00%
    DATAREPEATFACTORF: 18.275 
    Indexcolumn  ! Format        ! Dist. Values ! A/D ! NL ! Stats 
    -------------+---------- ----+--------------+-----+----+-------
    DSNAME       ! CHAR(44)      !        1.820 ! ASC ! N  ! OK    
                                                

Here I had a heart attack! 347,087 rows?!?!?!?!?!? How in the wide wide world of sports did that happen? Time to drill down into the contents of SYSCOPY with this little query:

SELECT ICTYPE , STYPE,  COUNT(*) 
FROM SYSIBM.SYSCOPY  
GROUP BY ICTYPE , STYPE            
;

Which returned these rather surprising results:

---------+---------+---------+
ICTYPE  STYPE                          
---------+---------+---------+
A       A                4             
B                       46             
C       L             1669             
C       O                4             
F                      100             
F       W               16             
I                        4             
L       M           344723             
M       R               18             
R                      151             
S                       62             
W                       18             
W       S                1             
Y                        2             
Z                      269             
DSNE610I NUMBER OF ROWS DISPLAYED IS 15

The L and M combination appears 344,723 times!!!

Grab your handy DB2 10 SQL reference and page on down to DB2 Catalog tables, SYSIBM.SYSCOPY and you will see:

ICTYPE CHAR(1) NOT NULL

Type of Operation:

A ALTER
B REBUILD INDEX
C CREATE
D CHECK DATA LOG(NO) (no log records for the range are available for RECOVER utility)
E RECOVER (to current point)
F COPY FULL YES
I COPY FULL NO
L SQL (type of operation)
M MODIFY RECOVERY utility
P RECOVER TOCOPY or RECOVER TORBA (partial recovery point)
Q QUIESCE
R LOAD REPLACE LOG(YES)
S LOAD REPLACE LOG(NO)
T TERM UTILITY command
V REPAIR VERSIONS utility
W REORG LOG(NO)
X REORG LOG(YES)
Y LOAD LOG(NO)
Z LOAD LOG(YES)

Now in my version the L entry has a ‘|’ by it to signify it is new. Scroll on down further to STYPE to read

STYPE CHAR(1) NOT NULL

Sub-type of operation:

When ICTYPE=L, the value is:

M Mass DELETE, TRUNCATE TABLE, DROP TABLE, or ALTER TABLE ROTATE PARTITION.
The LOWDSNUM column contains the table OBID of the affected table.

So, in other words, every time a program does a MASS DELETE it inserts a row into SYSCOPY. So then I ran another query to see when this all began and, hopefully, ended:

SELECT MAX(ICDATE), MIN(ICDATE) 
FROM SYSIBM.SYSCOPY                   
WHERE ICTYPE = 'L'                    
;                                     
---------+---------+---------+--------
                                      
---------+---------+---------+--------
121107  120828                        
DSNE610I NUMBER OF ROWS DISPLAYED IS 1

 

So we started getting records on the 28th August 2012 and the last one was the 7th November 2012 so in just about ten weeks even we managed 344,723 Mass Deletes!

So now, with my Sherlock Holmes deer stalker hat on, the question was “Why did it stop in November?” Happily we have a history here of APARs and that’s when this PMR bubbled to the Surface:

PM52724: MASS DELETES ENDS UP WITH LOCK ESCALATION ON SYSCOPY IN V10. BECAUSE PM30991 INTALLED CODE INSERTING L 12/01/04 PTF PECHANGE

 

I will let you go and read the text but suffice it to say IBM realized what a disaster this “logging” of Mass Deletes was and HIPERed a quick fix to stop it! Plus you can see the APAR that “brought in the dead mouse” PM30991.

PM30991 UK66327 Closed 2011-03-30

PM52724 UK80113 Closed 2012-07-03

So if you installed the PM30991 and not the PM52724 you probably have some cleaning up to do…

By the way I also rewrote the Ugly Duckling SQL:

  SELECT  T1.N1      
         ,T1.N2         
         ,T1.N3              
         ,T1.N4         
         ,T1.N5        
         ,T1.N6       
         ,T1.N7 
         ,T1.N8      
         ,T1.N9     
         ,T1.N10         
         ,T1.N11        
         ,T1.N12       
    FROM (                                   
   SELECT ICTS.DBNAME    AS N1   
         ,ICTS.TSNAME    AS N2      
         ,ICTS.TIMESTAMP AS N3      
         ,' '            AS N4     
         ,ICTS.DSNUM     AS N5     
         ,ICTS.ICTYPE    AS N6     
         ,DAYS ( :WORK-CURRENT-DATE ) - DAYS ( ICTS.TIMESTAMP ) AS N7
         ,ICTS.OTYPE     AS N8             
         ,ICTS.DSNAME    AS N9               
         ,ICTS.ICUNIT    AS N10              
         ,ICTS.INSTANCE  AS N11              
         ,ICTS.STYPE     AS N12              
     FROM SYSIBM.SYSCOPY ICTS                
    WHERE ICTS.ICBACKUP IN ('  ','LB','FC')  
      AND ICTS.OTYPE    = 'T'
UNION ALL    
   SELECT ICIX.DBNAME     AS N1    
         ,CAST(TABLES.TSNAME                 
          AS CHAR(8) CCSID EBCDIC) AS N2  
         ,ICIX.TIMESTAMP  AS N3      
         ,ICIX.TSNAME     AS N4
         ,ICIX.DSNUM      AS N5              
         ,ICIX.ICTYPE     AS N6              
         ,DAYS ( :WORK-CURRENT-DATE ) - DAYS ( ICIX.TIMESTAMP ) AS N7
         ,ICIX.OTYPE      AS N8              
         ,ICIX.DSNAME    AS N9               
         ,ICIX.ICUNIT    AS N10              
         ,ICIX.INSTANCE  AS N11              
        ,ICIX.STYPE     AS N12                
    FROM SYSIBM.SYSCOPY ICIX                  
        ,SYSIBM.SYSINDEXES INDEXES            
        ,SYSIBM.SYSTABLES TABLES              
   WHERE ICIX.ICBACKUP IN ('  ','LB','FC')    
     AND ICIX.OTYPE        = 'I'              
     AND ICIX.DBNAME      = INDEXES.DBNAME    
     AND ICIX.TSNAME      = INDEXES.INDEXSPACE
     AND INDEXES.TBNAME    = TABLES.NAME      
     AND INDEXES.TBCREATOR = TABLES.CREATOR   
 ) AS T1                                      
ORDER BY CAST(T1.N1 AS CHAR(8) CCSID EBCDIC)  
        ,CAST(T1.N2 AS CHAR(8) CCSID EBCDIC)  
        ,        N3 DESC                      
  FOR FETCH ONLY                              
  WITH UR                                     
  ;

 

To now perform like this:

Milliseconds:  55911  Service Units:   158836  Cost Category: A 
                                                                                 
QBNO QBTYPE CREATOR  TABLE NAME       MTCH IX METH PRNT TABL PRE  MXO 
PLNO TABNO  XCREATOR INDEX NAME ACTYP COLS ON OD   QBLK TYPE FTCH PSQ 
---- ------ -------- ---------- ----- ---- -- ---- ---- ---- ---- ---
   1 NCOSUB SYSIBM   SYSINDEXES I        0 N    0     2 T    S      0 
   1 3      SYSIBM   DSNDXX07   
   1 NCOSUB SYSIBM   SYSTABLES  I        2 N    1     2 T           0 
   2 4      SYSIBM   DSNDTX01
   1 NCOSUB SYSIBM   SYSCOPY    I        2 N    1     2 T    S      0 
   3 2      SYSIBM   DSNUCH01    
   2 UNIONA                              0 N    3     0 -           0 
   1 0   
   5 NCOSUB SYSIBM   SYSCOPY    R        0 N    0     2 T    S      0 
   1 1         
   ------ -------- ----------  ------ ---- -- ---- ---- ---- ----- ---

 

I am sure once I have deleted all the SYSCOPY rows (Note that we do not need to RECOVER on our test machine so I have the luxury of being able to delete the data – You, of course, cannot!) that it will return to being a nice little SQL!

 

After a large DELETE run which left only 2,365 rows followed by a REORG with inline RUNSTATS the original SQL now looks like:

 

Milliseconds:       672  Service Units:       1909  Cost Category: B  
                                                                               
QBNO QBTYPE CREATOR  TABLE NAME       MTCH IX METH PRNT TABL PRE  MXO
PLNO TABNO  XCREATOR INDEX NAME ACTYP COLS ON OD   QBLK TYPE FTCH PSQ
---- ------ -------- ---------- ----- ----- ---- -- ---- ---- ---- --
   1 SELECT R510PTFT T1         R        0 N     0    0 W    S      0
   1 5   
   1 SELECT                              0 N     3    0 -           0
   2 0   
   2 UNION                               0       3    1 -           0
   1 0 
   3 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0
   1 1  
   4 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0
   1 2  
   4 NCOSUB SYSIBM   SYSINDEXES I        2 N     1    2 T           0
   2 3      SYSIBM   DSNDXX02                 
   4 NCOSUB SYSIBM   SYSTABLES  I        2 N     1    2 T           0
   3 4      SYSIBM   DSNDTX01      
  ---- ------ -------- ------------------ ----- ---- -- ---- ---- ----

And my version:

Milliseconds:      631  Service Units:     1792  Cost Category: A          
                                                                                
QBNO QBTYPE CREATOR  TABLE NAME       MTCH IX METH PRNT TABL PRE  MXO
PLNO TABNO  XCREATOR INDEX NAME ACTYP COLS ON OD   QBLK TYPE FTCH PSQ
---- ------ -------- ---------- ----- ---- ---- -- ---- ---- ---- ---- 
   1 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0
   1 2       
   1 NCOSUB SYSIBM   SYSINDEXES I        2 N     1    2 T           0
   2 3      SYSIBM   DSNDXX02  
   1 NCOSUB SYSIBM   SYSTABLES  I        2 N     1    2 T           0
   3 4      SYSIBM   DSNDTX01 
   2 UNIONA                              0 N     3    0 -           0
   1 0             
   5 NCOSUB SYSIBM   SYSCOPY    R        0 N     0    2 T    S      0
   1 1   
   ---- ------ -------- ------------------ ----- ---- -- ---- ---- ----

Doesn’t look quite so impressive now…sniff…sniff

 

Here’s my SYSCOPY query for all cases:

SELECT ICTYPE, STYPE, MIN(ICDATE) AS OLDEST, MAX(ICDATE) AS NEWEST
     , COUNT(*) AS COUNT                                          
FROM SYSIBM.SYSCOPY                                               
GROUP BY ICTYPE , STYPE                                           
;                                                                 
---------+---------+---------+---------+---------+
ICTYPE  STYPE  OLDEST  NEWEST        COUNT           
---------+---------+---------+---------+---------+
A       A      121228  121228            4        
B              121228  130128           46       
C       L      100809  130204         1669    
C       O      120827  120827            4    
F              100809  130204          100     
F       W      100809  130204           16   
I              130131  130204            4
M       R      130102  130131           18         
R              120829  130130          151        
S              120829  130131           62      
W              100809  130204           18       
W       S      100809  100809            1     
Y              120828  120828            2    
Z              120828  130201          269    
DSNE610I NUMBER OF ROWS DISPLAYED IS 14

 

Clean Up

OK, so what can you do if you have 1000’s of these records? Well I would start with MODIFY RECOVER utilities to delete the bad guys. Your “normal” DB2 Database Maintenance jobs should take care of this for you but if you do not run these on a regular basis then start with this query:

SELECT A.DBNAME, A.TSNAME, A.DSNUM                              
      , MAX(DATE(A.TIMESTAMP)), MIN(DATE(A.TIMESTAMP)), COUNT(*)
FROM SYSIBM.SYSCOPY A                                           
WHERE A.ICTYPE = 'L'                                            
  AND A.STYPE  = 'M'                                            
  AND EXISTS (SELECT 1                                          
              FROM SYSIBM.SYSCOPY B                             
              WHERE A.DBNAME = B.DBNAME                         
                AND A.TSNAME = B.TSNAME                         
                AND (A.DSNUM  = B.DSNUM                         
                 OR (A.DSNUM > 0                                
                 AND B.DSNUM = 0 ))                             
                AND A.START_RBA < B.START_RBA                   
                AND B.ICTYPE = 'F')                             
GROUP BY A.DBNAME, A.TSNAME, A.DSNUM                            
FOR FETCH ONLY                                                  
WITH UR                                                         
;

The output shows you the DBNAME, TSNAME, DSNUM and counts for all of the “bad guys” that have at least one Full Image Copy *after* the bad guy was inserted:

---------+---------+---------+---------+---------+---------+---------+
DBNAME    TSNAME          DSNUM                                       
---------+---------+---------+---------+---------+---------+---------+
R510D0PT  R510S04             0  2016-01-26  2015-11-11           75  
R510D0PT  R510S10             0  2016-01-26  2015-11-11           75  
R510D0PT  R510S12             0  2016-01-26  2015-11-11           75  
R510D0PT  R510S14             0  2016-01-26  2015-11-11           75

 

This gives you the needed input to write a simple MODIFY RECOVER utility input like this:

 

MODIFY RECOVERY TABLESPACE R510D0PT.R510S04 DELETE DATE 20151203

Why did I use 2015-12-03 when in the query output I have 2015-11-11? That’s because I do not want to delete *all* of the Image Copy data in SYSCOPY – just the data from 2015-11-11 to 2015-12-02 (remember that MODIFY works up to the date *before* you enter). The output from the MODIFY looked like this:

 

DSNU000I    028 09:10:43.97 DSNUGUTC - OUTPUT START FOR UTILITY, 
            UTILID = PTFMO000MOU001
DSNU1044I   028 09:10:44.16 DSNUGTIS - PROCESSING SYSIN AS EBCDIC
DSNU050I    028 09:10:44.17 DSNUGUTC -  MODIFY RECOVERY TABLESPACE
            R510D0PT.R510S04 DELETE DATE 20151203
DSNU517I    -QA1B 028 09:10:44.28 DSNUMDEL 
            - SYSCOPY RECORD DELETED BY MODIFY UTILITY.
DSN=SETEST.R510D0PT.R510S04.D15142.T0635, VOL=SER=(CATLG), FILESEQNO=0
DSNU575I   -QA1B 028 09:10:44.49 DSNUMODA - MODIFY COMPLETED SUCCESSFULLY
DSNU010I    028 09:10:44.52 DSNUGBAC - UTILITY EXECUTION COMPLETE, 
            HIGHEST RETURN CODE=0

 

Now you must also IDCAMS Delete any, and all, of the dataset names output here.

Now re-running the original query gives:

---------+---------+---------+---------+---------+---------+---------
DBNAME    TSNAME          DSNUM                                      
---------+---------+---------+---------+---------+---------+---------
R510D0PT  R510S04             0  2016-01-26  2015-12-03           53 
R510D0PT  R510S10             0  2016-01-26  2015-11-11           75 
R510D0PT  R510S12             0  2016-01-26  2015-11-11           75 
R510D0PT  R510S14             0  2016-01-26  2015-11-11           75

 

24 type L & M records gone from between 2015-11-11 and 2015-12-02 and of course the object is not in COPY Pending status!

However, there are cases where you cannot do this straightaway (Perhaps never been image copied?). In these cases, the simplest method is to do an Image copy and then a Modify, but if the object is to big then you must make the DB2 Catalog updateable (ask your friendly Sysprog about this,) and simply use an SQL DELETE to remove all of the entries for an object *before* the last Full Image Copy.

Once you have removed all the fluff, remember to REORG SYSCOPY and RUNSTAT the indexes. Then it should be a *lot* thinner and make migrating a tad easier!

 

As always if you have any comments or questions please email me!

TTFN

Roy Boxwell

 

2015-10 DB2 Quick Security Audit – part 1

Is your DB2 Catalog opened with a PUBLIC grant?

Do you know how your DB2 z/OS System is looking on the security side ?

Today, I’d like to offer up some help around Audit and Security – always an issue. Please bear with me, as this is a really long newsletter. In fact, I had to make it into two parts. In this first part I wish to share a bunch of SQLs with you that will give a quick appraisal of how your DB2 system is looking – on the Security side of things. In the second part, we will then delve down more into Roles and conducting a deep analysis of your DB2 Catalog as well as quick review of any defaults that can cause security risks.

To get the ball rolling, let’s review any and all GRANTs on the DB2 Directory and Catalog tables. I know lots of shops where the whole Catalog is simply open with a PUBLIC grant, or two. Perhaps you should reconsider that these days? Remember that in the RUNSTATS data there are indeed data values stored in the Catalog.

Part 2 is dedicated to a deep Analysis of your DB2 Catalog (Newsletter 2015-11)

 

Let’s start the System appraisal with some SQLs… by applying the following laws:

0.Catalog and Directory Special Cases

1.With GRANT OPTION is a bad idea

2.Know your SYSADM userids

3.Is anything PUBLIC?

4.“Trusted” Trusted Contexts?

 

 

Catalog and Directory Special Cases

The first SQL is for Packages and Plans that access the Catalog:

SELECT A.GRANTOR
     , CASE A.GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
END AS GRANTORTYPE
     , A.GRANTEE
     , CASE A.GRANTEETYPE
       WHEN 'L' THEN 'ROLE        '
       WHEN 'P' THEN 'PLAN/PACKAGE'
       WHEN ' ' THEN 'AUTH ID     '
       ELSE          'UNKNOWN     '
END AS GRANTEETYPE
     , A.DBNAME
     , A.TCREATOR AS CREATOR
     , A.TTNAME   AS NAME
     , CASE A.AUTHHOWGOT
       WHEN ' ' THEN 'N/A         '
       WHEN 'B' THEN 'SYSTEM DBADM'
       WHEN 'C' THEN 'DBCTRL      '
       WHEN 'E' THEN 'SECADM      '
       WHEN 'G' THEN 'ACCESSCTRL  '
       WHEN 'K' THEN 'SQLADM      '
       WHEN 'L' THEN 'SYSCTRL     '
       WHEN 'M' THEN 'DBMAINT     '
       WHEN 'S' THEN 'SYSADM      '
       WHEN 'T' THEN 'DATAACCESS  '
       ELSE          'UNKNOWN     '
       END AS AUTHHOWGOT
     , A.ALTERAUTH
     , A.DELETEAUTH
     , A.INDEXAUTH
     , A.INSERTAUTH
     , A.SELECTAUTH
     , A.UPDATEAUTH
     , A.REFERENCESAUTH
     , A.TRIGGERAUTH
     , A.UPDATECOLS
     , A.REFCOLS
     , A.COLLID
     , HEX(A.CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSTABAUTH A
     , SYSIBM.SYSTABLES  B
WHERE NOT A.GRANTOR = A.GRANTEE
 AND A.GRANTEETYPE  = 'P'
 AND B.DBNAME IN ('DSNDB01', 'DSNDB06', 'DSNXSR' )
 AND B.TYPE    = 'T'
 AND B.CREATOR = A.TCREATOR
 AND B.NAME    = A.TTNAME
ORDER BY CREATOR, NAME, A.GRANTOR, A.GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;

Note that this query is decoding various fields for you as well – especially the Role of the Grantor/Grantee – and you will see this all the way through the following queries. You will also see the “FETCH FIRST 50 ROWS ONLY”, as you might have vastly more info than can easily be reviewed. Feel free to add predicates for your shop!

Now we want to see all the non-plan/package GRANTs:

SELECT A.GRANTOR
     , CASE A.GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTORTYPE
     , A.GRANTEE
     , CASE A.GRANTEETYPE
       WHEN 'L' THEN 'ROLE        '
       WHEN 'P' THEN 'PLAN/PACKAGE'
       WHEN ' ' THEN 'AUTH ID     '
       ELSE          'UNKNOWN     '
       END AS GRANTEETYPE
     , A.DBNAME
     , A.TCREATOR AS CREATOR
     , A.TTNAME   AS NAME
     , CASE A.AUTHHOWGOT
       WHEN ' ' THEN 'N/A         '
       WHEN 'B' THEN 'SYSTEM DBADM'
       WHEN 'C' THEN 'DBCTRL      '
       WHEN 'E' THEN 'SECADM      '
       WHEN 'G' THEN 'ACCESSCTRL  '
       WHEN 'K' THEN 'SQLADM      '
       WHEN 'L' THEN 'SYSCTRL     '
       WHEN 'M' THEN 'DBMAINT     '
       WHEN 'S' THEN 'SYSADM      '
       WHEN 'T' THEN 'DATAACCESS  '
       ELSE          'UNKNOWN     '
       END AS AUTHHOWGOT
     , A.ALTERAUTH
     , A.DELETEAUTH
     , A.INDEXAUTH
     , A.INSERTAUTH
     , A.SELECTAUTH
     , A.UPDATEAUTH
     , A.REFERENCESAUTH
     , A.TRIGGERAUTH
     , A.UPDATECOLS
     , A.REFCOLS
     , A.COLLID
     , HEX(A.CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSTABAUTH A
   , SYSIBM.SYSTABLES  B
WHERE NOT A.GRANTOR = A.GRANTEE
 AND NOT A.GRANTEETYPE = 'P'
 AND B.DBNAME IN ('DSNDB01', 'DSNDB06', 'DSNXSR' )
 AND B.TYPE    = 'T'
 AND B.CREATOR = A.TCREATOR
 AND B.NAME    = A.TTNAME
ORDER BY CREATOR, NAME, A.GRANTOR, A.GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;

Here it gets interesting when you have “G’s” in the xxxxAUTH columns of course! See later for the “First Law”.

Next, I would like to see whatever has been GRANTed to public:

SELECT A.GRANTOR
     , CASE A.GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTORTYPE
     , A.GRANTEE
     , CASE A.GRANTEETYPE
       WHEN 'L' THEN 'ROLE        '
       WHEN 'P' THEN 'PLAN/PACKAGE'
       WHEN ' ' THEN 'AUTH ID     '
       ELSE          'UNKNOWN     '
       END AS GRANTEETYPE
     , A.DBNAME
     , A.TCREATOR AS CREATOR
     , A.TTNAME   AS NAME
     , CASE A.AUTHHOWGOT
       WHEN ' ' THEN 'N/A         '
       WHEN 'B' THEN 'SYSTEM DBADM'
       WHEN 'C' THEN 'DBCTRL      '
       WHEN 'E' THEN 'SECADM      '
       WHEN 'G' THEN 'ACCESSCTRL  '
       WHEN 'K' THEN 'SQLADM      '
       WHEN 'L' THEN 'SYSCTRL     '
       WHEN 'M' THEN 'DBMAINT     '
       WHEN 'S' THEN 'SYSADM      '
       WHEN 'T' THEN 'DATAACCESS  '
       ELSE          'UNKNOWN     '
       END AS AUTHHOWGOT
     , A.ALTERAUTH
     , A.DELETEAUTH
     , A.INDEXAUTH
     , A.INSERTAUTH
     , A.SELECTAUTH
     , A.UPDATEAUTH
     , A.REFERENCESAUTH
     , A.TRIGGERAUTH
     , A.UPDATECOLS
     , A.REFCOLS
     , A.COLLID
     , HEX(A.CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSTABAUTH A
   , SYSIBM.SYSTABLES  B
WHERE NOT A.GRANTOR = A.GRANTEE
 AND B.DBNAME IN ('DSNDB01', 'DSNDB06', 'DSNXSR' )
 AND B.TYPE    = 'T'
 AND B.CREATOR = A.TCREATOR
 AND B.NAME    = A.TTNAME
 AND ( A.GRANTOR = 'PUBLIC'
    OR A.GRANTOR = 'PUBLIC*'
    OR A.GRANTEE = 'PUBLIC'
    OR A.GRANTEE = 'PUBLIC*' )
ORDER BY CREATOR, NAME, A.GRANTOR, A.GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;

Ok that’s the “special” case of the Catalog and Directory. Now onto the “normal” Catalog tables, to check what is in them, and whether it matches up to modern ideas of security, or not.

First Law: WITH GRANT OPTION is a bad idea

SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
 END AS GRANTORTYPE
    , GRANTEE
    , CASE GRANTEETYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
      END AS GRANTEETYPE
    , NAME
    , CASE AUTHHOWGOT
      WHEN 'C' THEN 'DBCTRL   '
      WHEN 'D' THEN 'DBADM     '
      WHEN 'E' THEN 'SECADM   '
      WHEN 'G' THEN 'ACCESSCTRL'
      WHEN 'L' THEN 'SYSCTRL   '
      WHEN 'M' THEN 'DBMAINT   '
      WHEN 'S' THEN 'SYSADM   '
      WHEN ' ' THEN 'N/A       '
      ELSE         'UNKNOWN   '
 END AS AUTHHOWGOT
    , CREATETABAUTH
    , CREATETSAUTH
    , DBADMAUTH
    , DBCTRLAUTH
    , DBMAINTAUTH
    , DISPLAYDBAUTH
    , DROPAUTH
    , IMAGCOPYAUTH
    , LOADAUTH
    , REORGAUTH
    , RECOVERDBAUTH
    , REPAIRAUTH
    , STARTDBAUTH
    , STATSAUTH
    , STOPAUTH
 FROM SYSIBM.SYSDBAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( CREATETABAUTH = 'G'
   OR CREATETSAUTH = 'G'
   OR DBADMAUTH     = 'G'
   OR DBCTRLAUTH   = 'G'
   OR DBMAINTAUTH   = 'G'
   OR DISPLAYDBAUTH = 'G'
   OR DROPAUTH     = 'G'
   OR IMAGCOPYAUTH = 'G'
   OR LOADAUTH     = 'G'
   OR REORGAUTH     = 'G'
   OR RECOVERDBAUTH = 'G'
   OR REPAIRAUTH   = 'G'
   OR STARTDBAUTH   = 'G'
   OR STATSAUTH     = 'G'
   OR STOPAUTH     = 'G' )
 ORDER BY NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE         'UNKNOWN'
 END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN 'P' THEN 'PLAN   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE         'UNKNOWN'
 END AS GRANTEETYPE
   , COLLID
   , NAME
   , CASE AUTHHOWGOT
     WHEN 'A' THEN 'PACKADM (COLLECTION *)   '
     WHEN 'C' THEN 'DBCTRL                  '
     WHEN 'D' THEN 'DBADM                     '
     WHEN 'E' THEN 'SECADM                   '
     WHEN 'G' THEN 'ACCESSCTRL               '
     WHEN 'L' THEN 'SYSCTRL                   '
     WHEN 'M' THEN 'DBMAINT                  '
     WHEN 'P' THEN 'PACKADM (NOT COLLECTION *)'
     WHEN 'S' THEN 'SYSADM                   '
     WHEN 'T' THEN 'DATAACCESS               '
     WHEN ' ' THEN 'N/A                       '
     ELSE         'UNKNOWN                   '
     END AS AUTHHOWGOT
   , BINDAUTH
   , COPYAUTH
   , EXECUTEAUTH
 FROM SYSIBM.SYSPACKAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( BINDAUTH   = 'G'
   OR COPYAUTH   = 'G'
   OR EXECUTEAUTH = 'G' )
 ORDER BY NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE         'UNKNOWN'
       END AS GRANTORTYPE
     , GRANTEE
     , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE         'UNKNOWN'
       END AS GRANTEETYPE
     , NAME
     , CASE AUTHHOWGOT
       WHEN 'C' THEN 'DBCTRL   '
       WHEN 'D' THEN 'DBADM     '
       WHEN 'E' THEN 'SECADM   '
       WHEN 'G' THEN 'ACCESSCTRL'
       WHEN 'L' THEN 'SYSCTRL   '
       WHEN 'M' THEN 'DBMAINT   '
       WHEN 'S' THEN 'SYSADM   '
       WHEN ' ' THEN 'N/A       '
       ELSE         'UNKNOWN   '
       END AS AUTHHOWGOT
     , BINDAUTH
     , EXECUTEAUTH
 FROM SYSIBM.SYSPLANAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( BINDAUTH   = 'G'
    OR EXECUTEAUTH = 'G' )
 ORDER BY NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE         'UNKNOWN'
       END AS GRANTORTYPE
     , GRANTEE
     , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE         'UNKNOWN'
       END AS GRANTEETYPE
     , QUALIFIER
     , NAME
     , CASE AUTHHOWGOT
       WHEN 'A' THEN 'PACKADM (COLLECTION *)   '
       WHEN 'C' THEN 'DBCTRL                   '
       WHEN 'D' THEN 'DBADM                     '
       WHEN 'E' THEN 'SECADM                   '
       WHEN 'G' THEN 'ACCESSCTRL               '
       WHEN 'L' THEN 'SYSCTRL                   '
       WHEN 'M' THEN 'DBMAINT                   '
       WHEN 'P' THEN 'PACKADM (NOT COLLECTION *)'
       WHEN 'S' THEN 'SYSADM                   '
       WHEN 'T' THEN 'DATAACCESS               '
       WHEN ' ' THEN 'N/A                       '
       ELSE         'UNKNOWN                   '
       END AS AUTHHOWGOT
     , CASE OBTYPE
       WHEN 'B' THEN 'BUFFER POOL '
       WHEN 'C' THEN 'COLLECTION   '
       WHEN 'D' THEN 'DISTINCT TYPE'
       WHEN 'R' THEN 'TABLE SPACE '
       WHEN 'S' THEN 'STORAGE GROUP'
       WHEN 'J' THEN 'JAR FILE     '
       ELSE         'UNKNOWN     '
       END       AS OBJECT_TYPE
     , USEAUTH
 FROM SYSIBM.SYSRESAUTH
 WHERE NOT GRANTOR = GRANTEE
 AND USEAUTH     = 'G'
 ORDER BY QUALIFIER, NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
      END AS GRANTORTYPE
    , GRANTEE
    , CASE GRANTEETYPE
      WHEN 'L' THEN 'ROLE             '
      WHEN 'P' THEN 'PLAN/PACKAGE     '
      WHEN 'R' THEN 'INTERNAL USE ONLY'
      WHEN ' ' THEN 'AUTH ID         '
      ELSE         'UNKNOWN         '
      END AS GRANTEETYPE
    , SCHEMA      AS CREATOR
    , SPECIFICNAME AS NAME
    , CASE ROUTINETYPE
      WHEN 'F' THEN 'UDF OR CAST FUNCTION'
      WHEN 'P' THEN 'STORED PROCEDURE   '
      ELSE         'UNKNOWN             '
      END       AS ROUTINETYPE
    , CASE AUTHHOWGOT
      WHEN '1' THEN 'GRANTOR SCHEMA.* AT TIME'
      WHEN 'E' THEN 'SECADM                 '
      WHEN 'G' THEN 'ACCESSCTRL             '
      WHEN 'L' THEN 'SYSCTRL                 '
      WHEN 'S' THEN 'SYSADM                 '
      WHEN 'T' THEN 'DATAACCESS             '
      WHEN ' ' THEN 'N/A                     '
      ELSE         'UNKNOWN                 '
      END AS AUTHHOWGOT
    , EXECUTEAUTH
    , COLLID
    , HEX(CONTOKEN) AS CONTOKEN
 FROM SYSIBM.SYSROUTINEAUTH
 WHERE NOT GRANTOR = GRANTEE
 AND EXECUTEAUTH = 'G'
 ORDER BY CREATOR , NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE         'UNKNOWN'
     END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE         'UNKNOWN'
     END AS GRANTEETYPE
   , SCHEMANAME
   , CASE AUTHHOWGOT
     WHEN '1' THEN 'GRANTOR SCHEMA.* AT TIME'
     WHEN 'E' THEN 'SECADM                 '
     WHEN 'G' THEN 'ACCESSCTRL             '
     WHEN 'L' THEN 'SYSCTRL                 '
     WHEN 'S' THEN 'SYSADM                 '
     ELSE         'UNKNOWN                 '
     END AS AUTHHOWGOT
   , CREATEINAUTH
   , ALTERINAUTH
   , DROPINAUTH
 FROM SYSIBM.SYSSCHEMAAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( CREATEINAUTH = 'G'
   OR   ALTERINAUTH = 'G'
   OR   DROPINAUTH   = 'G' )
 ORDER BY SCHEMANAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
      END AS GRANTORTYPE
    , GRANTEE
    , CASE GRANTEETYPE
      WHEN 'L' THEN 'ROLE            '
      WHEN 'P' THEN 'PLAN/PACKAGE     '
      WHEN 'R' THEN 'INTERNAL USE ONLY'
      WHEN ' ' THEN 'AUTH ID         '
      ELSE         'UNKNOWN         '
 END AS GRANTEETYPE
    , SCHEMA AS CREATOR
    , NAME
    , CASE AUTHHOWGOT
      WHEN ' ' THEN 'N/A       '
      WHEN 'E' THEN 'SECADM   '
      WHEN 'G' THEN 'ACCESSCTRL'
      WHEN 'L' THEN 'SYSCTRL   '
      WHEN 'S' THEN 'SYSADM   '
      WHEN 'T' THEN 'DATAACCESS'
      ELSE         'UNKNOWN   '
      END AS AUTHHOWGOT
    , ALTERAUTH
    , USEAUTH
    , COLLID
    , HEX(CONTOKEN) AS CONTOKEN
 FROM SYSIBM.SYSSEQUENCEAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( ALTERAUTH = 'G'
   OR   USEAUTH   = 'G' )
 ORDER BY CREATOR, NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
      END AS GRANTORTYPE
    , GRANTEE
    , CASE GRANTEETYPE
      WHEN 'L' THEN 'ROLE       '
      WHEN 'P' THEN 'PLAN/PACKAGE'
      WHEN ' ' THEN 'AUTH ID     '
      ELSE         'UNKNOWN     '
      END AS GRANTEETYPE
    , DBNAME
    , TCREATOR AS CREATOR
    , TTNAME   AS NAME
    , CASE AUTHHOWGOT
      WHEN ' ' THEN 'N/A         '
      WHEN 'B' THEN 'SYSTEM DBADM'
      WHEN 'C' THEN 'DBCTRL     '
      WHEN 'E' THEN 'SECADM     '
      WHEN 'G' THEN 'ACCESSCTRL '
      WHEN 'K' THEN 'SQLADM     '
      WHEN 'L' THEN 'SYSCTRL     '
      WHEN 'M' THEN 'DBMAINT     '
      WHEN 'S' THEN 'SYSADM     '
      WHEN 'T' THEN 'DATAACCESS '
      ELSE         'UNKNOWN     '
      END AS AUTHHOWGOT
    , ALTERAUTH
    , DELETEAUTH
    , INDEXAUTH
    , INSERTAUTH
    , SELECTAUTH
    , UPDATEAUTH
    , REFERENCESAUTH
    , TRIGGERAUTH
    , UPDATECOLS
    , REFCOLS
    , COLLID
    , HEX(CONTOKEN) AS CONTOKEN
 FROM SYSIBM.SYSTABAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( ALTERAUTH     = 'G'
   OR   DELETEAUTH     = 'G'
   OR   INDEXAUTH     = 'G'
   OR   INSERTAUTH     = 'G'
   OR   SELECTAUTH     = 'G'
   OR   UPDATEAUTH     = 'G'
   OR   REFERENCESAUTH = 'G'
   OR   TRIGGERAUTH   = 'G' )
 ORDER BY CREATOR, NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;
SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE         'UNKNOWN'
 END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE       '
     WHEN 'P' THEN 'PLAN/PACKAGE'
     WHEN ' ' THEN 'AUTH ID     '
     ELSE        'UNKNOWN     '
     END AS GRANTEETYPE
   , CASE AUTHHOWGOT
     WHEN ' ' THEN 'N/A       '
     WHEN 'C' THEN 'DBCTRL   '
     WHEN 'E' THEN 'SECADM   '
     WHEN 'G' THEN 'ACCESSCTRL'
     WHEN 'K' THEN 'SQLADM   '
     WHEN 'L' THEN 'SYSCTRL   '
     WHEN 'M' THEN 'DBMAINT   '
     WHEN 'O' THEN 'SYSOPR   '
     WHEN 'S' THEN 'SYSADM   '
     ELSE         'UNKNOWN   '
     END AS AUTHHOWGOT
   , BINDADDAUTH
   , BSDSAUTH
   , CREATEDBAAUTH
   , CREATEDBCAUTH
   , CREATESGAUTH
   , DISPLAYAUTH
   , RECOVERAUTH
   , STOPALLAUTH
   , STOSPACEAUTH
   , SYSADMAUTH
   , SYSOPRAUTH
   , TRACEAUTH
   , MON1AUTH
   , MON2AUTH
   , CREATEALIASAUTH
   , SYSCTRLAUTH
   , BINDAGENTAUTH
   , ARCHIVEAUTH
   , CREATETMTABAUTH
   , DEBUGSESSIONAUTH
   , EXPLAINAUTH
   , SQLADMAUTH
   , SDBADMAUTH
   , DATAACCESSAUTH
   , ACCESSCTRLAUTH
   , CREATESECUREAUTH
 FROM SYSIBM.SYSUSERAUTH
 WHERE NOT GRANTOR = GRANTEE
  AND ( BINDADDAUTH     = 'G'
   OR   BSDSAUTH         = 'G'
   OR   CREATEDBAAUTH   = 'G'
   OR   CREATEDBCAUTH   = 'G'
   OR   CREATESGAUTH     = 'G'
   OR   DISPLAYAUTH     = 'G'
   OR   RECOVERAUTH     = 'G'
   OR   STOPALLAUTH     = 'G'
   OR   STOSPACEAUTH     = 'G'
   OR   SYSADMAUTH       = 'G'
   OR   SYSOPRAUTH       = 'G'
   OR   TRACEAUTH       = 'G'
   OR   MON1AUTH         = 'G'
   OR   MON2AUTH         = 'G'
   OR   CREATEALIASAUTH = 'G'
   OR   SYSCTRLAUTH     = 'G'
   OR   BINDAGENTAUTH   = 'G'
   OR   ARCHIVEAUTH     = 'G'
   OR   CREATETMTABAUTH = 'G'
   OR   DEBUGSESSIONAUTH = 'G'
   OR   EXPLAINAUTH     = 'G'
   OR   SQLADMAUTH       = 'G'
   OR   SDBADMAUTH       = 'G'
   OR   DATAACCESSAUTH   = 'G'
   OR   ACCESSCTRLAUTH   = 'G'
   OR   CREATESECUREAUTH = 'G' )
 ORDER BY GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
 ;

Now you must review all of the output, and try to decide which, (if any!) of these should be allowed. I think they should all be not allowed, as you very quickly lose the ability to see who GRANTed what to whom!

Second Law: Know your SYSADM userids

If you do not know who is SYSADM that is a very bad place to be!

Here’s an SQL to help you find out:

SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTORTYPE
     , GRANTEE
     , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE        '
       WHEN 'P' THEN 'PLAN/PACKAGE'
       WHEN ' ' THEN 'AUTH ID     '
       ELSE          'UNKNOWN     '
       END AS GRANTEETYPE
     , CASE AUTHHOWGOT
       WHEN ' ' THEN 'N/A       '
       WHEN 'C' THEN 'DBCTRL    '
       WHEN 'E' THEN 'SECADM    '
       WHEN 'G' THEN 'ACCESSCTRL'
       WHEN 'K' THEN 'SQLADM    '
       WHEN 'L' THEN 'SYSCTRL   '
       WHEN 'M' THEN 'DBMAINT   '
       WHEN 'O' THEN 'SYSOPR    '
       WHEN 'S' THEN 'SYSADM    '
       ELSE          'UNKNOWN   '
       END AS AUTHHOWGOT
     , SYSADMAUTH
FROM SYSIBM.SYSUSERAUTH
WHERE NOT GRANTOR    = GRANTEE
  AND NOT SYSADMAUTH = ' '
ORDER BY GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;

Again, review the output *very* carefully and make very sure that all of the User Ids are well protected! One point to mention here is that lots of people use a surrogate User Id for Job scheduling (TWS, UC4, ESP, Control-M etc.) and normally these User Ids are very powerful, but they do *not* need to be SYSADM, and, if they are SYSADM, at least make them unavailable to TSO and remote Logon!

Third Law: Is anything PUBLIC?

There was a time, when nearly everything was PUBLIC, or even PUBLIC AT ALL LOCATIONS. These days this should never really be used, apart from exceptional circumstances. For example, the four SYSIBM.SYSDUMMYx tables can all safely get a

GRANT SELECT ON TABLE SYSIBM.SYSDUMMY1
                    , SYSIBM.SYSDUMMYE
                    , SYSIBM.SYSDUMMYA
                    , SYSIBM.SYSDUMMYU
TO PUBLIC ;

but you must weigh up the pros and cons of any other table being opened up like this.

SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTORTYPE
     , GRANTEE
     , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN 'P' THEN 'PLAN   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTEETYPE
     , CREATOR
     , TNAME    AS NAME
     , COLNAME  AS COLUMN
     , CASE PRIVILEGE
       WHEN 'R' THEN 'REFERENCES'
       WHEN ' ' THEN 'UPDATE    '
       ELSE          'UNKNOWN   '
       END AS AUTHHOWGOT
     , COLLID
     , HEX(CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSCOLAUTH
WHERE NOT GRANTOR = GRANTEE
 AND ( GRANTOR = 'PUBLIC'
    OR GRANTEE = 'PUBLIC' )
ORDER BY NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
, CASE GRANTORTYPE
WHEN 'L' THEN 'ROLE   '
WHEN ' ' THEN 'AUTH ID'
ELSE          'UNKNOWN'
END AS GRANTORTYPE
, GRANTEE
, CASE GRANTEETYPE
WHEN 'L' THEN 'ROLE   '
WHEN 'P' THEN 'PLAN   '
WHEN ' ' THEN 'AUTH ID'
ELSE          'UNKNOWN'
END AS GRANTEETYPE
, NAME
, CASE AUTHHOWGOT
WHEN 'C' THEN 'DBCTRL    '
WHEN 'D' THEN 'DBADM     '
WHEN 'E' THEN 'SECADM    '
WHEN 'G' THEN 'ACCESSCTRL'
WHEN 'L' THEN 'SYSCTRL   '
WHEN 'M' THEN 'DBMAINT   '
WHEN 'S' THEN 'SYSADM    '
WHEN ' ' THEN 'N/A       '
ELSE          'UNKNOWN   '
END AS AUTHHOWGOT
, CREATETABAUTH
, CREATETSAUTH
, DBADMAUTH
, DBCTRLAUTH
, DBMAINTAUTH
, DISPLAYDBAUTH
, DROPAUTH
, IMAGCOPYAUTH
, LOADAUTH
, REORGAUTH
, RECOVERDBAUTH
, REPAIRAUTH
, STARTDBAUTH
, STATSAUTH
, STOPAUTH
FROM SYSIBM.SYSDBAUTH
WHERE NOT GRANTOR = GRANTEE
AND ( GRANTOR = 'PUBLIC'
OR GRANTEE = 'PUBLIC' )
ORDER BY NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTORTYPE
     , GRANTEE
     , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE   '
      WHEN 'P' THEN 'PLAN   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTEETYPE
     , COLLID
     , NAME
     , CASE AUTHHOWGOT
       WHEN 'A' THEN 'PACKADM (COLLECTION *)    '
       WHEN 'C' THEN 'DBCTRL                    '
       WHEN 'D' THEN 'DBADM                     '
       WHEN 'E' THEN 'SECADM                    '
       WHEN 'G' THEN 'ACCESSCTRL                '
       WHEN 'L' THEN 'SYSCTRL                   '
       WHEN 'M' THEN 'DBMAINT                   '
       WHEN 'P' THEN 'PACKADM (NOT COLLECTION *)'
       WHEN 'S' THEN 'SYSADM                    '
       WHEN 'T' THEN 'DATAACCESS                '
       WHEN ' ' THEN 'N/A                       '
       ELSE          'UNKNOWN                   '
       END AS AUTHHOWGOT
     , BINDAUTH
     , COPYAUTH
     , EXECUTEAUTH
FROM SYSIBM.SYSPACKAUTH
WHERE NOT GRANTOR = GRANTEE
 AND ( GRANTOR = 'PUBLIC'
    OR GRANTOR = 'PUBLIC*'
    OR GRANTEE = 'PUBLIC'
    OR GRANTEE = 'PUBLIC*' )
ORDER BY NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
     , CASE GRANTORTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
      END AS GRANTORTYPE
    , GRANTEE
    , CASE GRANTEETYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END AS GRANTEETYPE
     , NAME
     , CASE AUTHHOWGOT
       WHEN 'C' THEN 'DBCTRL    '
       WHEN 'D' THEN 'DBADM     '
       WHEN 'E' THEN 'SECADM    '
       WHEN 'G' THEN 'ACCESSCTRL'
       WHEN 'L' THEN 'SYSCTRL   '
       WHEN 'M' THEN 'DBMAINT   '
       WHEN 'S' THEN 'SYSADM    '
       WHEN ' ' THEN 'N/A       '
       ELSE          'UNKNOWN   '
       END AS AUTHHOWGOT
     , BINDAUTH
     , EXECUTEAUTH
FROM SYSIBM.SYSPLANAUTH
WHERE NOT GRANTOR = GRANTEE
 AND  GRANTEE = 'PUBLIC'
ORDER BY NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
    , CASE GRANTORTYPE
      WHEN 'L' THEN 'ROLE   '
      WHEN ' ' THEN 'AUTH ID'
      ELSE          'UNKNOWN'
 END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTEETYPE
   , QUALIFIER
   , NAME
   , CASE AUTHHOWGOT
     WHEN 'A' THEN 'PACKADM (COLLECTION *)    '
     WHEN 'C' THEN 'DBCTRL                    '
     WHEN 'D' THEN 'DBADM                     '
     WHEN 'E' THEN 'SECADM                    '
     WHEN 'G' THEN 'ACCESSCTRL                '
     WHEN 'L' THEN 'SYSCTRL                   '
     WHEN 'M' THEN 'DBMAINT                   '
     WHEN 'P' THEN 'PACKADM (NOT COLLECTION *)'
     WHEN 'S' THEN 'SYSADM                    '
     WHEN 'T' THEN 'DATAACCESS                '
     WHEN ' ' THEN 'N/A                       '
     ELSE          'UNKNOWN                   '
     END AS AUTHHOWGOT
   , CASE OBTYPE
     WHEN 'B' THEN 'BUFFER POOL  '
     WHEN 'C' THEN 'COLLECTION   '
     WHEN 'D' THEN 'DISTINCT TYPE'
     WHEN 'R' THEN 'TABLE SPACE  '
     WHEN 'S' THEN 'STORAGE GROUP'
     WHEN 'J' THEN 'JAR FILE     '
     ELSE          'UNKNOWN      '
     END        AS OBJECT_TYPE
   , USEAUTH
 FROM SYSIBM.SYSRESAUTH
 WHERE NOT GRANTOR = GRANTEE
   AND  GRANTEE = 'PUBLIC'
 ORDER BY QUALIFIER, NAME, GRANTOR, GRANTEE
 FETCH FIRST 50 ROWS ONLY
 WITH UR
;
SELECT GRANTOR
, CASE GRANTORTYPE
WHEN 'L' THEN 'ROLE   '
WHEN ' ' THEN 'AUTH ID'
ELSE          'UNKNOWN'
END AS GRANTORTYPE
, GRANTEE
, CASE GRANTEETYPE
WHEN 'L' THEN 'ROLE             '
WHEN 'P' THEN 'PLAN/PACKAGE     '
WHEN 'R' THEN 'INTERNAL USE ONLY'
WHEN ' ' THEN 'AUTH ID          '
ELSE          'UNKNOWN          '
END AS GRANTEETYPE
, SCHEMA       AS CREATOR
, SPECIFICNAME AS NAME
, CASE ROUTINETYPE
WHEN 'F' THEN 'UDF OR CAST FUNCTION'
WHEN 'P' THEN 'STORED PROCEDURE    '
ELSE          'UNKNOWN             '
END        AS ROUTINETYPE
, CASE AUTHHOWGOT
WHEN '1' THEN 'GRANTOR SCHEMA.* AT TIME'
WHEN 'E' THEN 'SECADM                  '
WHEN 'G' THEN 'ACCESSCTRL              '
WHEN 'L' THEN 'SYSCTRL                 '
WHEN 'S' THEN 'SYSADM                  '
WHEN 'T' THEN 'DATAACCESS              '
WHEN ' ' THEN 'N/A                     '
ELSE          'UNKNOWN                 '
END AS AUTHHOWGOT
, EXECUTEAUTH
, COLLID
, HEX(CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSROUTINEAUTH
WHERE NOT GRANTOR = GRANTEE
AND  GRANTEE = 'PUBLIC'
ORDER BY CREATOR , NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTEETYPE
   , SCHEMANAME
   , CASE AUTHHOWGOT
     WHEN '1' THEN 'GRANTOR SCHEMA.* AT TIME'
     WHEN 'E' THEN 'SECADM                  '
     WHEN 'G' THEN 'ACCESSCTRL              '
     WHEN 'L' THEN 'SYSCTRL                 '
     WHEN 'S' THEN 'SYSADM                  '
     ELSE          'UNKNOWN                 '
     END AS AUTHHOWGOT
   , CREATEINAUTH
   , ALTERINAUTH
   , DROPINAUTH
FROM SYSIBM.SYSSCHEMAAUTH
WHERE NOT GRANTOR = GRANTEE
 AND  GRANTEE = 'PUBLIC'
ORDER BY SCHEMANAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE             '
     WHEN 'P' THEN 'PLAN/PACKAGE     '
     WHEN 'R' THEN 'INTERNAL USE ONLY'
     WHEN ' ' THEN 'AUTH ID          '
     ELSE          'UNKNOWN          '
     END AS GRANTEETYPE
   , SCHEMA AS CREATOR
   , NAME
   , CASE AUTHHOWGOT
     WHEN ' ' THEN 'N/A       '
     WHEN 'E' THEN 'SECADM    '
     WHEN 'G' THEN 'ACCESSCTRL'
     WHEN 'L' THEN 'SYSCTRL   '
     WHEN 'S' THEN 'SYSADM    '
     WHEN 'T' THEN 'DATAACCESS'
     ELSE          'UNKNOWN   '
     END AS AUTHHOWGOT
   , ALTERAUTH
   , USEAUTH
   , COLLID
   , HEX(CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSSEQUENCEAUTH
WHERE NOT GRANTOR = GRANTEE
AND  GRANTEE = 'PUBLIC'
ORDER BY CREATOR, NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE        '
     WHEN 'P' THEN 'PLAN/PACKAGE'
     WHEN ' ' THEN 'AUTH ID     '
     ELSE          'UNKNOWN     '
END AS GRANTEETYPE
   , DBNAME
   , TCREATOR AS CREATOR
   , TTNAME   AS NAME
   , CASE AUTHHOWGOT
     WHEN ' ' THEN 'N/A         '
     WHEN 'B' THEN 'SYSTEM DBADM'
     WHEN 'C' THEN 'DBCTRL      '
     WHEN 'E' THEN 'SECADM      '
     WHEN 'G' THEN 'ACCESSCTRL  '
     WHEN 'K' THEN 'SQLADM      '
     WHEN 'L' THEN 'SYSCTRL     '
     WHEN 'M' THEN 'DBMAINT     '
     WHEN 'S' THEN 'SYSADM      '
     WHEN 'T' THEN 'DATAACCESS  '
     ELSE          'UNKNOWN     '
     END AS AUTHHOWGOT
   , ALTERAUTH
   , DELETEAUTH
   , INDEXAUTH
   , INSERTAUTH
   , SELECTAUTH
   , UPDATEAUTH
   , REFERENCESAUTH
   , TRIGGERAUTH
   , UPDATECOLS
   , REFCOLS
   , COLLID
   , HEX(CONTOKEN) AS CONTOKEN
FROM SYSIBM.SYSTABAUTH
WHERE NOT GRANTOR = GRANTEE
 AND ( GRANTOR = 'PUBLIC'
  OR GRANTOR = 'PUBLIC*'
  OR GRANTEE = 'PUBLIC'
  OR GRANTEE = 'PUBLIC*' )
ORDER BY CREATOR, NAME, GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;
SELECT GRANTOR
   , CASE GRANTORTYPE
     WHEN 'L' THEN 'ROLE   '
     WHEN ' ' THEN 'AUTH ID'
     ELSE          'UNKNOWN'
     END AS GRANTORTYPE
   , GRANTEE
   , CASE GRANTEETYPE
     WHEN 'L' THEN 'ROLE        '
     WHEN 'P' THEN 'PLAN/PACKAGE'
     WHEN ' ' THEN 'AUTH ID     '
     ELSE          'UNKNOWN     '
     END AS GRANTEETYPE
   , CASE AUTHHOWGOT
     WHEN ' ' THEN 'N/A       '
     WHEN 'C' THEN 'DBCTRL    '
     WHEN 'E' THEN 'SECADM    '
     WHEN 'G' THEN 'ACCESSCTRL'
     WHEN 'K' THEN 'SQLADM    '
     WHEN 'L' THEN 'SYSCTRL   '
     WHEN 'M' THEN 'DBMAINT   '
     WHEN 'O' THEN 'SYSOPR    '
     WHEN 'S' THEN 'SYSADM    '
     ELSE          'UNKNOWN   '
END AS AUTHHOWGOT
   , BINDADDAUTH
   , BSDSAUTH
   , CREATEDBAAUTH
   , CREATEDBCAUTH
   , CREATESGAUTH
   , DISPLAYAUTH
   , RECOVERAUTH
   , STOPALLAUTH
   , STOSPACEAUTH
   , SYSADMAUTH
   , SYSOPRAUTH
   , TRACEAUTH
   , MON1AUTH
   , MON2AUTH
   , CREATEALIASAUTH
   , SYSCTRLAUTH
   , BINDAGENTAUTH
   , ARCHIVEAUTH
   , CREATETMTABAUTH
   , DEBUGSESSIONAUTH
   , EXPLAINAUTH
   , SQLADMAUTH
   , SDBADMAUTH
   , DATAACCESSAUTH
   , ACCESSCTRLAUTH
   , CREATESECUREAUTH
FROM SYSIBM.SYSUSERAUTH
WHERE NOT GRANTOR = GRANTEE
AND  GRANTEE = 'PUBLIC'
ORDER BY GRANTOR, GRANTEE
FETCH FIRST 50 ROWS ONLY
WITH UR
;

Once again, go through the output and make informed decisions! The Hacker loves PUBLIC.

Fourth Law: “Trusted” Trusted Contexts?

Trusted Contexts are great, but have you got some that are a bit too open? Have you – by accident – left the back door open? Run this to find out:

SELECT ENABLED
     , NAME
     , CONTEXTID
     , DEFINER
     , CASE DEFINERTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END        AS DEFINERTYPE
     , DEFAULTROLE
     , CASE OBJECTOWNERTYPE
       WHEN 'L' THEN 'ROLE   '
       WHEN ' ' THEN 'AUTH ID'
       ELSE          'UNKNOWN'
       END        AS OBJECTOWNERTYPE
     , ALLOWPUBLIC
     , AUTHENTICATEPUBLIC
     , DEFAULTSECURITYLABEL
FROM SYSIBM.SYSCONTEXT
WHERE ALLOWPUBLIC        = 'Y'
  AND AUTHENTICATEPUBLIC = 'N'
ORDER BY 3
FETCH FIRST 50 ROWS ONLY
WITH UR
;

 

Allowing public access, but without authentication, is not a good idea.

Now all we have done is validate the DB2 Catalog. What about seeing what is happening on your machine? Have you anything in place that can give you 100% coverage of audit issues? With SOFTWARE ENGINEERING’s  SQL WorkloadExpert for DB2 z/OS you can audit everything that is running in your enterprise. For example here is a view of the Audit pop-up window:

 

DB2 z/OS newsletter 2015-10: DB2 Quick Security Audit -Part 1

 

One of the options here, is to see exactly how many Authorization Ids are running at your shop, or even what the SYSADMs of the world have been doing. All handy stuff and available real-time!

I hope you enjoyed this first part and thanks for getting this far. Next up is knowing your Roles and Authorization Ids.

As always, any questions or comments would be most welcome!

TTFN,

Roy Boxwell

2015-05 Top 10 Things to Ignore for DB2 z/OS

 

This newsletter was inspired by a recent article I read in the “Enterprise Systems Magazine” called “Top 10 Ways to Waste Money on CPU”. Why not the Top 10 things to ignore?

 

DB2 z/OS things you could ignore but most definitely should not!

So here’s my little list, in no particular order, of things you could ignore but most definitely should not!

  1 SQL DELETE statements in mega-million  tables SQL DELETE statements in mega-million  tables when a REORG DISCARD would kill two birds with one stone. (I love that phrase) Anyway, after 500,000 singleton deletes the tablespace probably needs a REORG anyway and so why not do two in one? A bit of a no-brainer really.
  2 LOB columns LOB columns, whose size would *easily* fit inside an inline LOB or even a VARCHAR. LOBs are still slow and cumbersome to use, but inline LOBs are great. If you can use ‘em – do so!
  3 BP0 being used for *everything* by default… BP0 being used for *everything* by default… Please split the BP s into groups!!! BP0 is only, and I mean ONLY, for the Catalog and Directory. That way you can actually keep the size low and spare some memory for other BPs. LOB and XML tablespaces get their own BP. Tables and Indexes are split. Sort gets its own. You get the idea ?
  4 Utility jobs still based on 1990’s ideas Utility jobs still based on 1990’s ideas. Are you still running a RUNSTATS to see if a REORG is needed? Are you running REORGs without inline RUNSTATS? Are your RUNSTATS using FREQVAL and, if required, HISTOGRAM?
  5 Death by “indexiphication”. Death by “indexiphication”. Do you have tables with more than three indexes? Do you have ten or more indexes? Time to look for INCLUDE usage and LASTUSED Timestamps here!
  6 PLAN_TABLE explosion PLAN_TABLE explosion. Do you have multiple PLAN_TABLEs in production? Are you REORGing, RUNSTATSing and Image Copying them on a regular basis? Are you purging them of rubbish data on a regular basis?
  7 Are your ZPARMs up to date? Have you checked the Rules of Thumb in regard to ZPARMS since they were last set back in the 80’s? Now is the time to do a review of all the ZPARMS to see where you can really get performance boosts. (For example the default SRTPOOL In DB2 10 is now 10,000k but in DB2 V8 and 9 it was just 2,000k)
 8 Are you removing garbage from the DB2 Catalog and Directory ? Are you removing garbage from the DB2 Catalog and Directory ? Do you really need all the packages and versions of those packages from 1989 these days? If a table gets RUNSTATSed that these ancient, never executed, packages uses then it should trigger a review of the access paths, which could, of course, flag up problems where no real problem exists.
  9  COMMIT frequency. You never need to check or change this do you…
 10  Training IDUG, Insight, and RUGs etc. you can never ever get enough info about how things work and how to make things better.

 

One thing you should certainly NOT ignore, is my newsletter! I have lots of exciting topics coming up in 2015 and I’ll also let you know about our webinars.

Upcoming Newsletters

  • SOUNDEX and other cool features part 4 – update for DB2 10 & all new for DB2 11
  • BAD Data Day
  • Overloaded Log
  • A real CLUSTER Buster

 

As usual, any comments or questions are welcome!

TTFN

Roy Boxwell