Re: checkpointer continuous flushing
От | Fabien COELHO |
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Тема | Re: checkpointer continuous flushing |
Дата | |
Msg-id | alpine.DEB.2.10.1507261656380.25082@sto обсуждение исходный текст |
Ответ на | Re: checkpointer continuous flushing (Fabien COELHO <coelho@cri.ensmp.fr>) |
Ответы |
Re: checkpointer continuous flushing
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Список | pgsql-hackers |
Hello, Attached is very minor v5 update which does a rebase & completes the cleanup of doing a full sort instead of a chuncked sort. >> Attached is an updated version of the patch which turns the sort option >> into a boolean, and also include the sort time in the checkpoint log. >> >> There is still an open question about whether the sorting buffer allocation >> is lost on some signals and should be reallocated in such event. > > In such case, probably the allocation should be managed from > CheckpointerMain, and the lazy allocation could remain for other callers (I > guess just "initdb"). > > > More open questions: > > - best name for the flush option (checkpoint_flush_to_disk, > checkpoint_flush_on_write, checkpoint_flush, ...) > > - best name for the sort option (checkpoint_sort, > checkpoint_sort_buffers, checkpoint_sort_ios, ...) > > > Other nice-to-have inputs: > > - tests on a non-linux system with posix_fadvise > (FreeBSD? others?) > > - tests on a large dedicated box > > > Attached are some scripts to help with testing, if someone's feels like that: > > - cp_test.sh: run some tests, to adapt to one's setup... > > - cp_test_count.pl: show percent of late transactions > > - avg.py: show stats about stuff > > sh> grep 'progress: ' OUTPUT_FILE | cut -d' ' -f4 | avg.py > > *BEWARE* that if pgbench got stuck some "0" data are missing, > look for the actual tps in the output file and for the line > count to check whether it is the case... some currently submitted > patch on pgbench helps, see https://commitfest.postgresql.org/5/199/ As this pgbench patch is now in master, pgbench is less likely to get stuck, but check nevertheless that the number of progress line matches the expected number. -- Fabien.
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