Log File Sync等待超高案例浅析
IT科技类资讯 2025-10-07 15:22:19
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等待超复制HISTOGRAM DATA FOR LFS AND OTHER RELATED WAITS: APPROACH: Look at the wait distribution for log file sync waits by looking at"wait_time_milli". Look at the high wait times then see if you can correlate those with other related wait events. INST_ID EVENT WAIT_TIME_MILLI WAIT_COUNT ---------- ---------------------------------------- --------------- ---------- 1 log file sync 1 4363 1 log file sync 2 835 1 log file sync 4 1650 1 log file sync 8 4937 1 log file sync 16 146252 1 log file sync 32 606674 1 log file sync 64 263377 1 log file sync 128 253254 1 log file sync 256 2 1 log file switch completion 1 124 1 log file switch completion 2 9 1 log file switch completion 4 19 1 log file switch completion 8 21 1 log file switch completion 16 35 1 log file switch completion 32 97 1 log file switch completion 64 133 1 log file switch completion 128 326 1 log file switch completion 256 1736 1 log file switch completion 512 3042 1 log file switch completion 1024 2020 1 log file parallel write 1 0 1 log file parallel write 2 0 1 log file parallel write 4 80 1 log file parallel write 8 2142 1 log file parallel write 16 170987 1 log file parallel write 32 779205 1 log file parallel write 64 311463 1 log file parallel write 128 79688 1 log file parallel write 256 42763 1 log file parallel write 512 13052 1 log file parallel write 1024 20468 1 log file parallel write 2048 14020 1 log file parallel write 4096 921 1 log file parallel write 8192 96 1 log file parallel write 16384 18 1 log file parallel write 32768 18 1 log file parallel write 65536 8 1 log file parallel write 131072 2 1 LGWR wait for redo copy 1 8516 1 LGWR wait for redo copy 2 20 1 LGWR wait for redo copy 4 19 1 LGWR wait for redo copy 8 20 1 LGWR wait for redo copy 16 11 ORDERED BY WAIT_TIME_MILLI INST_ID EVENT WAIT_TIME_MILLI WAIT_COUNT ---------- ---------------------------------------- --------------- ---------- 1 log file sync 1 4363 1 log file switch completion 1 124 1 log file parallel write 1 0 1 LGWR wait for redo copy 1 8516 1 log file sync 2 835 1 log file switch completion 2 9 1 log file parallel write 2 0 1 LGWR wait for redo copy 2 20 1 log file sync 4 1650 1 log file switch completion 4 19 1 log file parallel write 4 80 1 LGWR wait for redo copy 4 19 1 log file sync 8 4937 1 log file switch completion 8 21 1 log file parallel write 8 2142 1 LGWR wait for redo copy 8 20 1 log file sync 16 146252 1 log file switch completion 16 35 1 log file parallel write 16 170987 1 LGWR wait for redo copy 16 11 1 log file sync 32 606674 1 log file switch completion 32 97 1 log file parallel write 32 779205 1 log file sync 64 263377 1 log file switch completion 64 133 1 log file parallel write 64 311463 1 log file sync 128 253254 1 log file switch completion 128 326 1 log file parallel write 128 79688 1 log file sync 256 2 1 log file switch completion 256 1736 1 log file parallel write 256 42763 1 log file switch completion 512 3042 1 log file parallel write 512 13052 1 log file switch completion 1024 2020 1 log file parallel write 1024 20468 1 log file parallel write 2048 14020 1 log file parallel write 4096 921 1 log file parallel write 8192 96 1 log file parallel write 16384 18 1 log file parallel write 32768 18 1 log file parallel write 65536 8 1 log file parallel write 131072 2 REDO WRITE STATS "redo write time"in centiseconds (100 per second) 11.1: "redo write broadcast ack time"in centiseconds (100 per second) 11.2: "redo write broadcast ack time"in microseconds (1000 per millisecond) VERSION INST_ID NAME VALUE MILLISECONDS ----------------- ---------- ---------------------------------------- --------------------- ------------------- 10.2.0.5.0 1 redo write time 9551524 95515240.000 10.2.0.5.0 1 redo writer latching time 51 10.2.0.5.0 1 redo writes 1434931 AWR WORST AVG LOG FILE SYNC SNAPS: 1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.19.20.21.22.23.24.25.26.27.28.29.30.31.32.33.34.35.36.37.38.39.40.41.42.43.44.45.46.47.48.49.50.51.52.53.54.55.56.57.58.59.60.61.62.63.64.65.66.67.68.69.70.71.72.73.74.75.76.77.78.79.80.81.82.83.84.85.86.87.88.89.90.91.92.93.94.95.96.97.98.99.100.101.102.103.104.105.106.107.108.109.110.111.112.113.