In trying to isolate an issue where the PostgreSQL 'explain analyze' is showing "odd results" (namely, negative time estimates on queries), Tom Lane wrote a quick C program to test gettimeofday() (program attached) ... the results on a 4.9-PRERELEASE kernel of Sep 20 14:16:48 ADT 2003 shows: neptune# time ./timetest out of order tv_sec: 1070068479 99040, prev 1070069174 725235 out of order tv_usec: 1070068479 99040, prev 1070069174 725235 out of order tv_sec: 1070069175 19687, prev 1070068479 99040 out of order tv_usec: 1070069175 19687, prev 1070068479 99040 out of order tv_sec: 1070068499 99377, prev 1070069194 625573 out of order tv_usec: 1070068499 99377, prev 1070069194 625573 out of order tv_sec: 1070069194 808542, prev 1070068499 99377 ^C1.171u 23.461s 0:24.68 99.7% 5+169k 1+0io 0pf+0w One person on the list has tried the same script on a 5.2 kernel, and reports seeing similar results, but after a longer period of time (~30min) ... In most (all?) cases, the offset appears to be ~+/-695 secs ... Linux ppl on the list, running the same problem, seem to be able to reproduce the issue, except they are only finding differences of 1 microsecond, and then only on older kernels (2.2.x, apparently) ... those running newer Linux kernels are reporting a clean run ... Known problem? ---- Marc G. Fournier Hub.Org Networking Services (http://www.hub.org) Email: scrappy_at_hub.org Yahoo!: yscrappy ICQ: 7615664
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