> Running the attached test program shows on BSD/OS 4.3: > > write 0.000360 > write & fsync 0.001391
I think the "write & fsync" pays for the previous "write" test (same filename). > write, close & fsync 0.001308 > open o_fsync, write 0.000924 I have tried to modify the program to more closely resemble WAL writes (all writes to WAL are 8k), the file is usually already open, and test larger (16k) transactions. [EMAIL PROTECTED]:~> test_sync1 write 0.000625 write & fsync 0.016748 write & fdatasync 0.006650 write, close & fsync 0.017084 write, close & fdatasync 0.006890 open o_dsync, write 0.015997 open o_dsync, one write 0.007128 For the last line xlog.c would need to be modified, but the measurements seem to imply that it is only worth it on platforms that have O_DSYNC but not fdatasync. Andreas
test_sync1.c
Description: test_sync1.c
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