如何診斷cursor pin s wait on x 系列二，cursorpin

如何診斷cursor pin s wait on x 系列二，cursorpin

如何分析診斷收集資訊

1.       查看AWR 報告中high paring 和high version部分內容

 

具體查看這幾個部分的內容：'SQLordered by Parse Calls' or 'SQL ordered by Version Count'

 

 

SQL ordered by Parse Calls關於這部分中的sql 解析執行是否過高，或者能否減小來。

SQL ordered by Version Count關於這部分中的high version sql ，需要找出為啥他們不能共用，可以通過 v$sql_shared_cursor  視圖尋找原因

 

2.    systemstats 和errorstack 的關注點

對於systemstats 和errorstack 時效性非常重要。需要在問題發生時刻進行dump ，否則過時採集的資訊是無效的。在一個高速啟動並執行系統中，那些holders and waiter 進程轉瞬即逝。

 

 

根據AWR 的 load profile 部分內容可以初步判斷出 系統 sql 解析情況：

如果看到hard parses 很多，表明系統可能沒有使用綁定變數，或者有新的sql 上線。

 

對於high version counts  也會導致 cursor:ping S wait on X

使用V$SQL_SHARED_CURSOR可以尋找出 sql 不能共用的原因

有些bug可能會導致 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 可能會導致 cursor pin s wait on x :

NB	Bug	Fixed	Description
5650841	Hang / deadlock from ANALYZE of cluster index
16191248	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
14295250	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
14191508	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
14176247	11.2.0.4, 12.1.0.1	Many child cursors using Adaptive Cursor Sharing with binds (due to BIND_EQUIV_FAILURE)
18292893	12.1.0.2, 12.2.0.0	Jobs don't execute per schedule with a large number of PDBs
18018515	12.2.0.0	High CPU in qctHasFakeBind (can cause 'cursor: pin S wait on X' waits)
16448569	11.2.0.4, 12.1.0.2, 12.2.0.0	PQ hang/deadlock possible - "cursor: pin S wait on X" waits
16400122	12.2.0.0	Spikes in library cache mutex contention for SQL using SQL Plan Baseline
15850031	11.2.0.4, 12.2.0.0	Rare instance hang: deadlock between 'row cache lock' and 'cursor: pin S wait for X'
14469756	12.2.0.0	Partition pruning causes delay in TBL$OR$IDX$PART$NUM
14302813	11.2.0.4, 12.2.0.0	QC blocked / parse hang for parallel DML executed from remote stored procedure
14029891	11.2.0.4, 12.1.0.1	mutex deadlock having SQL baselines on recursive dictionary cursor
11927619	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
11855965	11.2.0.3, 12.1.0.1	Truncate partition takes long time doing recursive delete on MLOG$
10213073	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
10171273	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
9944129	11.2.0.1.BP12, 11.2.0.2, 12.1.0.1	SQL not shared due to INST_DRTLD_MISMATCH with global transaction
9935787	11.2.0.3, 12.1.0.1	Long parse time for large inlists - can cause 'cursor: pin S wait on X' waits
9694101	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
9499302	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
9472669	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
8508078	11.2.0.2, 12.1.0.1	Contention from many concurrent bad SQLs - superseded
12432089	11.2.0.3	library cache lock/cursor: pin S wait on X with parallel partition stats gathering
8441239	11.2.0.1	Library cache lock waits if long running TRUNCATE in progress
8348464	11.1.0.7.2, 11.2.0.1	CREATE SYNONYM and CREATE PACKAGE may incorrectly invalidate objects
7234778	11.2.0.1	Unnecessary "cursor: pin S wait on X" waits
5485914	10.2.0.4	Mutex self deadlock on explain / trace of remote mapped SQL
6143420	10.2.0.5, 11.1.0.6	Deadlock involving "ROW CACHE LOCK" on dc_users AND "CURSOR: PIN S WAIT ON X"
6011045	10.2.0.5.5	DBMS_STATS causes deadlock between 'cursor: pin S wait on X' and 'library cache lock'
7462072	10.2.0.4.3, 10.2.0.5	Unnecessary "cursor: pin S wait on X" waits
5983020	10.2.0.4	MMON deadlock with user session executing ALTER USER
7226463	10.2.0.5	EXECUTE IMMEDIATE no releasing mutex or library cache pin
+	5907779	10.2.0.4	Self deadlock hang on "cursor: pin S wait on X" (typically from DBMS_STATS)