Yesterday I’ve got a weird problem with Adaptive Cursor Sharing. I’m not sure yet about the issue, but it seems to be related to cursor sharing histograms. Hopefully one day I will blog about what I’ve learnt from this experience.
To better monitor the problem on that specific query, I’ve prepared this script (tested on 12.1.0.2):
COLUMN Shareable HEADING 'S|H|A|R|E|A|B|L|E'
COLUMN "Bind-Aware" HEADING 'B|I|N|D| |A|W|A|R|E'
COLUMN Sensitive HEADING 'S|E|N|S|I|T|I|V|E'
COLUMN Reoptimizable HEADING 'R|E|O|P|T|I|M|I|Z|A|B|L|E'
BREAK on child_number on Execs on "Gets/Exec" on "Ela/Exec" on "Sensitive" on "Shareable" on "Bind-Aware" on bucket0 on bucket1 on bucket2 on cnt on "Reoptimizable" on is_resolved_adaptive_plan
select * from (select *
from (
select
s.child_number,
s.plan_hash_value,
executions as Execs,
round(buffer_gets/executions) as "Gets/Exec",
round(elapsed_time/executions) as "Ela/Exec",
is_bind_sensitive as "Sensitive",
is_shareable as "Shareable",
is_bind_aware as "Bind-Aware",
to_char(h.bucket_id) as bucket, h.count as cnt,
is_reoptimizable as "Reoptimizable",
is_resolved_adaptive_plan,
"UNBOUND_CURSOR", "SQL_TYPE_MISMATCH", "OPTIMIZER_MISMATCH",
"OUTLINE_MISMATCH", "STATS_ROW_MISMATCH", "LITERAL_MISMATCH",
"FORCE_HARD_PARSE", "EXPLAIN_PLAN_CURSOR", "BUFFERED_DML_MISMATCH",
"PDML_ENV_MISMATCH", "INST_DRTLD_MISMATCH", "SLAVE_QC_MISMATCH",
"TYPECHECK_MISMATCH", "AUTH_CHECK_MISMATCH", "BIND_MISMATCH",
"DESCRIBE_MISMATCH", "LANGUAGE_MISMATCH", "TRANSLATION_MISMATCH",
"BIND_EQUIV_FAILURE", "INSUFF_PRIVS", "INSUFF_PRIVS_REM",
"REMOTE_TRANS_MISMATCH", "LOGMINER_SESSION_MISMATCH", "INCOMP_LTRL_MISMATCH",
"OVERLAP_TIME_MISMATCH", "EDITION_MISMATCH", "MV_QUERY_GEN_MISMATCH",
"USER_BIND_PEEK_MISMATCH", "TYPCHK_DEP_MISMATCH", "NO_TRIGGER_MISMATCH",
"FLASHBACK_CURSOR", "ANYDATA_TRANSFORMATION", "PDDL_ENV_MISMATCH",
"TOP_LEVEL_RPI_CURSOR", "DIFFERENT_LONG_LENGTH", "LOGICAL_STANDBY_APPLY",
"DIFF_CALL_DURN", "BIND_UACS_DIFF", "PLSQL_CMP_SWITCHS_DIFF",
"CURSOR_PARTS_MISMATCH", "STB_OBJECT_MISMATCH", "CROSSEDITION_TRIGGER_MISMATCH",
"PQ_SLAVE_MISMATCH", "TOP_LEVEL_DDL_MISMATCH", "MULTI_PX_MISMATCH",
"BIND_PEEKED_PQ_MISMATCH", "MV_REWRITE_MISMATCH", "ROLL_INVALID_MISMATCH",
"OPTIMIZER_MODE_MISMATCH", "PX_MISMATCH", "MV_STALEOBJ_MISMATCH",
"FLASHBACK_TABLE_MISMATCH", "LITREP_COMP_MISMATCH", "PLSQL_DEBUG",
"LOAD_OPTIMIZER_STATS", "ACL_MISMATCH", "FLASHBACK_ARCHIVE_MISMATCH",
"LOCK_USER_SCHEMA_FAILED", "REMOTE_MAPPING_MISMATCH", "LOAD_RUNTIME_HEAP_FAILED",
"HASH_MATCH_FAILED", "PURGED_CURSOR", "BIND_LENGTH_UPGRADEABLE",
"USE_FEEDBACK_STATS"
from v$sql s
join v$sql_cs_histogram h
on (s.sql_id=h.sql_id and
s.child_number=h.child_number and
s.con_id=h.con_id
)
join v$sql_shared_cursor shc
on (shc.sql_id=h.sql_id and
shc.child_number=h.child_number and
s.con_id=shc.con_id
)
where s.sql_id='&sql_id'
)
pivot (sum(cnt) for (bucket) IN ('0' AS Bucket0,'1' AS Bucket1,'2' AS Bucket2))
)
unpivot (result FOR reason_type IN ("UNBOUND_CURSOR",
"SQL_TYPE_MISMATCH", "OPTIMIZER_MISMATCH",
"OUTLINE_MISMATCH", "STATS_ROW_MISMATCH", "LITERAL_MISMATCH",
"FORCE_HARD_PARSE", "EXPLAIN_PLAN_CURSOR", "BUFFERED_DML_MISMATCH",
"PDML_ENV_MISMATCH", "INST_DRTLD_MISMATCH", "SLAVE_QC_MISMATCH",
"TYPECHECK_MISMATCH", "AUTH_CHECK_MISMATCH", "BIND_MISMATCH",
"DESCRIBE_MISMATCH", "LANGUAGE_MISMATCH", "TRANSLATION_MISMATCH",
"BIND_EQUIV_FAILURE", "INSUFF_PRIVS", "INSUFF_PRIVS_REM",
"REMOTE_TRANS_MISMATCH", "LOGMINER_SESSION_MISMATCH", "INCOMP_LTRL_MISMATCH",
"OVERLAP_TIME_MISMATCH", "EDITION_MISMATCH", "MV_QUERY_GEN_MISMATCH",
"USER_BIND_PEEK_MISMATCH", "TYPCHK_DEP_MISMATCH", "NO_TRIGGER_MISMATCH",
"FLASHBACK_CURSOR", "ANYDATA_TRANSFORMATION", "PDDL_ENV_MISMATCH",
"TOP_LEVEL_RPI_CURSOR", "DIFFERENT_LONG_LENGTH", "LOGICAL_STANDBY_APPLY",
"DIFF_CALL_DURN", "BIND_UACS_DIFF", "PLSQL_CMP_SWITCHS_DIFF",
"CURSOR_PARTS_MISMATCH", "STB_OBJECT_MISMATCH", "CROSSEDITION_TRIGGER_MISMATCH",
"PQ_SLAVE_MISMATCH", "TOP_LEVEL_DDL_MISMATCH", "MULTI_PX_MISMATCH",
"BIND_PEEKED_PQ_MISMATCH", "MV_REWRITE_MISMATCH", "ROLL_INVALID_MISMATCH",
"OPTIMIZER_MODE_MISMATCH", "PX_MISMATCH", "MV_STALEOBJ_MISMATCH",
"FLASHBACK_TABLE_MISMATCH", "LITREP_COMP_MISMATCH", "PLSQL_DEBUG",
"LOAD_OPTIMIZER_STATS", "ACL_MISMATCH", "FLASHBACK_ARCHIVE_MISMATCH",
"LOCK_USER_SCHEMA_FAILED", "REMOTE_MAPPING_MISMATCH", "LOAD_RUNTIME_HEAP_FAILED",
"HASH_MATCH_FAILED", "PURGED_CURSOR", "BIND_LENGTH_UPGRADEABLE",
"USE_FEEDBACK_STATS"))
where result='Y'
order by child_number;The result is something similar (in my case it has 26 child cursors):
R
E
O
B P
S S I T
E H N I
N A D M
S R I
I E A Z
T A W A
I B A B
V L R L
CHILD_NUMBER PLAN_HASH_VALUE EXECS Gets/Exec Ela/Exec E E E E I BUCKET0 BUCKET1 BUCKET2 REASON_TYPE R
------------ --------------- ---------- ---------- ---------- - - - - - ---------- ---------- ---------- ----------------------------- -
0 2293695281 455 2466 14464 Y Y Y N 0 455 0 ROLL_INVALID_MISMATCH Y
2293695281 BIND_EQUIV_FAILURE Y
1 1690560038 99 13943 103012 Y Y Y N 0 99 0 ROLL_INVALID_MISMATCH Y
1690560038 BIND_EQUIV_FAILURE Y
2 3815006743 541 43090 230245 Y Y Y N 0 541 0 BIND_EQUIV_FAILURE Y
3815006743 ROLL_INVALID_MISMATCH Y
3 1483632464 251 4111 18940 Y Y Y N 49 202 0 ROLL_INVALID_MISMATCH Y
1483632464 BIND_EQUIV_FAILURE Y
4 3815006743 1152 42632 220730 Y Y Y N 0 1000 0 BIND_EQUIV_FAILURE Y
3815006743 ROLL_INVALID_MISMATCH Y
5 3922835573 150 39252 184176 Y Y Y N 0 150 0 ROLL_INVALID_MISMATCH Y
3922835573 BIND_EQUIV_FAILURE Y
6 767857637 3 4731 124707 Y Y Y N 0 3 0 ROLL_INVALID_MISMATCH Y
767857637 BIND_EQUIV_FAILURE Y
7 767857637 11 4739 71119 Y Y Y N 0 11 0 BIND_EQUIV_FAILURE Y
8 2800467281 1 307 249727 Y Y Y N 0 1 0 BIND_EQUIV_FAILURE Y
9 3123241890 536 2982 14428 Y Y Y N 6 530 0 ROLL_INVALID_MISMATCH Y
3123241890 BIND_EQUIV_FAILURE Y
10 3125518635 17 315 16492 Y Y Y N 16 1 0 ROLL_INVALID_MISMATCH Y
3125518635 BIND_EQUIV_FAILURE Y
11 2184442252 130 4686 40188 Y Y Y N 0 130 0 ROLL_INVALID_MISMATCH Y
2184442252 BIND_EQUIV_FAILURE Y
12 3815006743 553 42765 231391 Y Y Y N 0 553 0 ROLL_INVALID_MISMATCH Y
3815006743 BIND_EQUIV_FAILURE Y
13 1166983254 47 14193 111256 Y Y Y N 0 47 0 BIND_EQUIV_FAILURE Y
1166983254 ROLL_INVALID_MISMATCH Y
14 2307602173 2 38 45922 Y Y Y N 2 0 0 BIND_EQUIV_FAILURE Y
2307602173 ROLL_INVALID_MISMATCH Y
15 767857637 11 4304 59617 Y Y Y N 0 11 0 BIND_EQUIV_FAILURE Y
767857637 ROLL_INVALID_MISMATCH Y
16 3108045525 2 34591 176749 Y N N N 1 1 0 ROLL_INVALID_MISMATCH Y
3108045525 LOAD_OPTIMIZER_STATS Y
3108045525 BIND_EQUIV_FAILURE Y
17 3108045525 6 1794 33335 Y Y Y N 4 2 0 BIND_EQUIV_FAILURE Y
3108045525 ROLL_INVALID_MISMATCH Y
18 2440443365 470 2009 13361 Y Y Y N 0 470 0 ROLL_INVALID_MISMATCH Y
2440443365 BIND_EQUIV_FAILURE Y
19 4079924956 15 2032 19773 Y Y Y N 8 7 0 ROLL_INVALID_MISMATCH Y
4079924956 BIND_EQUIV_FAILURE Y
20 777919270 32 2675 18260 Y Y Y N 11 21 0 BIND_EQUIV_FAILURE Y
777919270 ROLL_INVALID_MISMATCH Y
21 1428146033 63 13929 111116 Y Y Y N 0 63 0 ROLL_INVALID_MISMATCH Y
1428146033 BIND_EQUIV_FAILURE Y
22 3815006743 218 43673 234642 Y Y Y N 0 218 0 BIND_EQUIV_FAILURE Y
3815006743 ROLL_INVALID_MISMATCH Y
23 277802667 1 62 99268 Y Y Y N 1 0 0 BIND_EQUIV_FAILURE Y
277802667 ROLL_INVALID_MISMATCH Y
24 3898025231 3 2364 111231 Y Y Y N 0 3 0 BIND_EQUIV_FAILURE Y
3898025231 ROLL_INVALID_MISMATCH Y
25 767857637 2 6495 169363 Y Y Y N 0 2 0 ROLL_INVALID_MISMATCH Y
767857637 BIND_EQUIV_FAILURE Y
26 3690167092 100 2998 20138 Y Y Y N 0 100 0 BIND_EQUIV_FAILURE Y
3690167092 ROLL_INVALID_MISMATCH YIt’s a quick way to get the relevant information in a single result.
Off course, if you need deeper details, you should consider something more powerful like SQLd360 from Mauro Pagano.
Credits: I’ve got the unpivot idea (and copied that part of the code) from this post by Timur Akhmadeev.
—
Ludo