log file switch (checkpoint incomplete)的問題定位
阿新 • • 發佈：2017-08-20
tab diff margin 等待 data- center end bus wid
查看等待時間，發現日誌切換在等待。
半小時切換了23次，redo日誌我看了一下，一個為512M。
最直接的方法是看下數據塊修改的情況，再去查SQL。一眼看去就是物化視圖MV_CONTRACT_INFO導致，70,211,408是修改數據庫的數量。換算成數據量是70211408*8/1024/1024=535.6G。只是這個是最大的redo。事實上真實的比這個小，即使小，也非常可觀。
今天測試環境下應用慢。發現數據庫出了問題，直接上AWR報告。因為是虛擬機。所以不用貼cpu的個數，能夠發現負載高。
|
Snap Id |
Snap Time | Sessions | Cursors/Session | |
|---|---|---|---|---|
| Begin Snap: | 15257 | 30-Jun-15 09:30:57 | 558 | 5.3 |
| End Snap: | 15258 | 30-Jun-15 10:00:27 | 582 | 5.7 |
| Elapsed: | 29.50 (mins) | |||
| DB Time: | 717.00 (mins) |
查看等待時間，發現日誌切換在等待。
Top 10 Foreground Events by Total Wait Time
| Event | Waits | Total Wait Time (sec) | Wait Avg(ms) | % DB time | Wait Class |
|---|---|---|---|---|---|
| log file switch (checkpoint incomplete) | 350 | 11.3K | 32229 | 26.2 | Configuration |
| db file sequential read | 569,141 | 8433.8 | 15 | 19.6 | User I/O |
| read by other session | 1,228,260 | 6279.9 | 5 | 14.6 | User I/O |
| buffer busy waits | 452,194 | 6138 | 14 | 14.3 | Concurrency |
| DB CPU | 3121.5 | 7.3 | |||
| enq: TX - row lock contention | 300 | 1934.5 | 6448 | 4.5 | Application |
| direct path read | 45,561 | 1647.4 | 36 | 3.8 | User I/O |
| db file scattered read | 89,177 | 1617.5 | 18 | 3.8 | User I/O |
| db file parallel read | 29,761 | 1079.4 | 36 | 2.5 | User I/O |
| log file sync | 9,864 | 720.7 | 73 | 1.7 | Commit |
半小時切換了23次，redo日誌我看了一下，一個為512M。
| Statistic | Total | per Hour |
|---|---|---|
| log switches (derived) | 23 | 46.78 |
最直接的方法是看下數據塊修改的情況，再去查SQL。一眼看去就是物化視圖MV_CONTRACT_INFO導致，70,211,408是修改數據庫的數量。換算成數據量是70211408*8/1024/1024=535.6G。只是這個是最大的redo。事實上真實的比這個小，即使小，也非常可觀。
非常明顯。是有人在刷新物化視圖，通知開發不要在上班時間內刷新物化視圖。
Segments by DB Blocks Changes
- % of Capture shows % of DB Block Changes for each top segment compared
- with total DB Block Changes for all segments captured by the Snapshot
| Owner | Tablespace Name | Object Name | Subobject Name | Obj. Type | DB Block Changes | % of Capture |
|---|---|---|---|---|---|---|
| LCAM_ZC_0130 | WZ | MV_CONTRACT_INFO | TABLE | 70,211,408 | 99.91 | |
| LCAM_SC | SPROC4GD_DATA | GCP_D_S_ALL | TABLE | 34,864 | 0.05 | |
| LCAM_PUB_CS | LCAM_SYS_TBS | SYS_LOB0001127099C00014$$ | LOB | 5,104 | 0.01 | |
| LCAM_PUB_15630 | WZ | SOA_SERVICE_LOAD_RESULT | TABLE | 5,024 | 0.01 | |
| LCAM_PUB_CS | LCAM_SYS_TBS | PK_LOAD_ID | INDEX | 4,752 | 0.01 |
log file switch (checkpoint incomplete)的問題定位