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Home -> Community -> Usenet -> c.d.o.server -> V$FILESTAT reports very long average write times.
Does anyone have some clues as to why average write times are so high?
I'm pretty certain the underlying disk i/o is ok. I can consistently get 15mb/sec write times in UNIX outside of Oracle. Since this is an IBM ESS F20, I was hoping to get 5 milliseconds or less average write times. Another reason I don't believe basic disk i/o is a problem because the "temp" datafiles are written vey fast. I believe TEMP tablespace files bypass SGA management so I think the write times of 100+ milleseconds has something to do with an incorrect setting in init.ora.
The statspack report for "log file sync" and "db file parallel write" don't seem particularly high either.
Any insights helpful.
Excerpt of V$FILESTAT:
FILE# PHYBLKWRT AVG NAME
----- ------------ ----------
3 301,856 2.53 /oracle/PRD/sapdata10/temp_1/temp.data1
59 231,850 4.20 /oracle/PRD/sapdata9/temp_3/temp.data3
226 152,052 168.04 /oracle/PRD/sapdata10/undo_4/undo.data4
227 142,045 153.58 /oracle/PRD/sapdata10/undo_5/undo.data5
224 133,753 143.53 /oracle/PRD/sapdata10/undo_2/undo.data2
89 131,659 3.01 /oracle/PRD/sapdata9/temp_4/temp.data4
223 127,839 120.86 /oracle/PRD/sapdata10/undo_1/undo.data1
225 112,634 164.32 /oracle/PRD/sapdata10/undo_3/undo.data3
213 84,993 54.67
/oracle/PRD/sapdata19/btabi_52/btabi.data52
202 77,022 47.74
/oracle/PRD/sapdata14/btabd_61/btabd.data61
210 71,352 61.42
/oracle/PRD/sapdata14/btabi_50/btabi.data50
209 71,122 78.15
/oracle/PRD/sapdata14/btabi_49/btabi.data49
212 71,119 69.95
/oracle/PRD/sapdata18/btabi_51/btabi.data51
43 62,353 4.66 /oracle/PRD/sapdata10/temp_2/temp.data2
217 60,988 62.50
/oracle/PRD/sapdata16/btabi_54/btabi.data54
185 53,049 49.01
/oracle/PRD/sapdata5/btabd_51/btabd.data51
215 48,020 67.56
/oracle/PRD/sapdata16/btabi_53/btabi.data53
79 45,837 813.26
/oracle/PRD/sapdata12/btabd_6/btabd.data6
76 45,452 701.26
/oracle/PRD/sapdata12/btabd_5/btabd.data5
111 44,678 271.20
/oracle/PRD/sapdata11/btabd_17/btabd.data17
81 38,824 418.90
/oracle/PRD/sapdata12/btabd_7/btabd.data7
220 33,049 55.34
/oracle/PRD/sapdata16/btabi_55/btabi.data55
206 31,687 52.19
/oracle/PRD/sapdata23/btabi_46/btabi.data46
30 25,805 168.83
/oracle/PRD/sapdata15/btabi_2/btabi.data2
216 25,473 56.59
/oracle/PRD/sapdata10/btabd_66/btabd.data66
91 25,347 261.95
/oracle/PRD/sapdata12/btabd_8/btabd.data8
70 23,580 132.89
/oracle/PRD/sapdata15/btabi_4/btabi.data4
29 23,310 156.33 /oracle/PRD/sapdata6/btabd_2/btabd.data2
7 22,224 121.96 /oracle/PRD/sapdata6/btabd_1/btabd.data1
233 22,168 87.17
/oracle/PRD/sapdata10/el46cd_1/el46cd.data1
196 19,395 49.56
Excerpt of statspack report:
Avg
Total Wait wait
Waits
Event Waits Timeouts Time (s) (ms)
---------------------------- ------------ ---------- ---------- ------ -------- db file sequential read 9,950,267 0 31,547 3 323.6 db file scattered read 1,497,870 0 3,186 2 48.7 buffer busy waits 180,454 0 2,108 12 5.9 log file sync 31,751 10 260 8 1.0 db file parallel write 12,484 0 226 18 0.4 SQL*Net more data to client 48,367 0 154 3 1.6 db file parallel read 2,787 0 105 38 0.1 enqueue 138 9 69 5020.0 Received on Wed Jun 16 2004 - 11:45:32 CDT
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