如何分析诊断收集信息
1. 查看AWR 报告中high paring 和high version部分内容
具体查看这几个部分的内容：'SQLordered by Parse Calls' or 'SQL ordered by Version Count'
SQL ordered by Parse Calls关于这部分中的sql 解析执行是否过高，或者能否减小来。
SQL ordered by Version Count关于这部分中的high version sql ，需要找出为啥他们不能共享，可以通过 v$sql_shared_cursor 视图查找原因
2. systemstats 和errorstack 的关注点
对于systemstats 和errorstack 时效性非常重要。需要在问题发生时刻进行dump ，否则过时采集的信息是无效的。在一个高速运行的系统中，那些holders and waiter 进程转瞬即逝。
根据AWR 的 load profile 部分内容可以初步判断出 系统 sql 解析情况：
如果看到hard parses 很多，表明系统可能没有使用绑定变量，或者有新的sql 上线。
对于high version counts 也会导致 cursor:ping S wait on X
使用V$SQL_SHARED_CURSOR可以查找出 sql 不能共享的原因
有些bug可能会导致 high version counts：
Document 1057392.8 Bug 10157392 - High version counts forSQL with binds (BIND_MISMATCH)
Document 9689310.8 Bug 9689310 - Excessive child cursors /high VERSION_COUNT / OERI:17059 due to bind mismatch
Bug 可能会导致 cursor pin s wait on x :
NB |
Bug |
Fixed |
Description |
Hang / deadlock from ANALYZE of cluster index |
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12.1.0.1.1, 12.1.0.2, 12.2.0.0 |
Hang from concurrent drop of on-commit materialized views or using DBMS_REDEFINITION |
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11.2.0.4, 12.1.0.1 |
Long parse time for large query with many nested views due to much time in epxression analysis code |
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11.2.0.3.8, 11.2.0.3.BP16, 11.2.0.4, 12.1.0.1 |
Slow row cache load due to SEG$ and INDSUBPART$ queries |
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11.2.0.4, 12.1.0.1 |
Many child cursors using Adaptive Cursor Sharing with binds (due to BIND_EQUIV_FAILURE) |
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12.1.0.2, 12.2.0.0 |
Jobs don't execute per schedule with a large number of PDBs |
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12.2.0.0 |
High CPU in qctHasFakeBind (can cause 'cursor: pin S wait on X' waits) |
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11.2.0.4, 12.1.0.2, 12.2.0.0 |
PQ hang/deadlock possible - "cursor: pin S wait on X" waits |
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12.2.0.0 |
Spikes in library cache mutex contention for SQL using SQL Plan Baseline |
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11.2.0.4, 12.2.0.0 |
Rare instance hang: deadlock between 'row cache lock' and 'cursor: pin S wait for X' |
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12.2.0.0 |
Partition pruning causes delay in TBL$OR$IDX$PART$NUM |
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11.2.0.4, 12.2.0.0 |
QC blocked / parse hang for parallel DML executed from remote stored procedure |
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11.2.0.4, 12.1.0.1 |
mutex deadlock having SQL baselines on recursive dictionary cursor |
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11.2.0.1.BP11, 11.2.0.2.BP07, 11.2.0.3, 12.1.0.1 |
DBMS_STATS slow on interval composite partitions |
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11.2.0.3, 12.1.0.1 |
Truncate partition takes long time doing recursive delete on MLOG$ |
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11.2.0.2.8, 11.2.0.2.BP18, 11.2.0.3, 12.1.0.1 |
CREATE SYNONYM and CREATE PACKAGE may incorrectly invalidate objects |
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11.2.0.2.8, 11.2.0.2.BP08, 11.2.0.3, 12.1.0.1 |
Long parse time with non-equi subpartitioning under interval partitioning |
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11.2.0.1.BP12, 11.2.0.2, 12.1.0.1 |
SQL not shared due to INST_DRTLD_MISMATCH with global transaction |
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11.2.0.3, 12.1.0.1 |
Long parse time for large inlists - can cause 'cursor: pin S wait on X' waits |
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10.2.0.5.7, 11.2.0.2, 12.1.0.1 |
Hang / deadlock between "cursor: pin S wait on X" and "library cache lock" involving dictionary objects |
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10.2.0.5.5, 11.1.0.7.7, 11.2.0.1.BP08, 11.2.0.2, 12.1.0.1 |
Improve concurrent mutex request handling |
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11.2.0.1.BP12, 11.2.0.2, 12.1.0.1 |
'cursor: pin S wait on X' waits for invalid SQL over DB link |
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11.2.0.2, 12.1.0.1 |
Contention from many concurrent bad SQLs - superseded |
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11.2.0.3 |
library cache lock/cursor: pin S wait on X with parallel partition stats gathering |
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11.2.0.1 |
Library cache lock waits if long running TRUNCATE in progress |
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11.1.0.7.2, 11.2.0.1 |
CREATE SYNONYM and CREATE PACKAGE may incorrectly invalidate objects |
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11.2.0.1 |
Unnecessary "cursor: pin S wait on X" waits |
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10.2.0.4 |
Mutex self deadlock on explain / trace of remote mapped SQL |
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10.2.0.5, 11.1.0.6 |
Deadlock involving "ROW CACHE LOCK" on dc_users AND "CURSOR: PIN S WAIT ON X" |
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10.2.0.5.5 |
DBMS_STATS causes deadlock between 'cursor: pin S wait on X' and 'library cache lock' |
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10.2.0.4.3, 10.2.0.5 |
Unnecessary "cursor: pin S wait on X" waits |
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10.2.0.4 |
MMON deadlock with user session executing ALTER USER |
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10.2.0.5 |
EXECUTE IMMEDIATE no releasing mutex or library cache pin |
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+ |
10.2.0.4 |
Self deadlock hang on "cursor: pin S wait on X" (typically from DBMS_STATS) |