Re: [SQL] inserts/updates problem under stressing !
От | Vadim Mikheev |
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Тема | Re: [SQL] inserts/updates problem under stressing ! |
Дата | |
Msg-id | 379BFF7E.BD57269E@krs.ru обсуждение исходный текст |
Ответ на | Re: [SQL] inserts/updates problem under stressing ! (Oleg Bartunov <oleg@sai.msu.su>) |
Ответы |
Re: [SQL] inserts/updates problem under stressing !
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Список | pgsql-sql |
Oleg Bartunov wrote: > > > > > SELECT FOR UPDATE will not help: if there was no record for > > particular key then nothing will be locked and two records with > > the same key will be inserted. > > > > Oleg, use LOCK IN SHARE ROW EXCLUSIVE MODE. > > Thanks Vadim. Just tried this, but still I see a difference between > count hits (accumulated) from db and access_log. In my test these numbers are: > 95 and 109. So I lost 14 hits ! And no errors ! > In my handler I have now: > > my $sth = $dbh->do("LOCK TABLE hits IN SHARE ROW EXCLUSIVE MODE"); > my $sth = $dbh->do("SELECT acc_hits($1)") || die $dbh->errstr; > > am I right ? You should run LOCK and SELECT inside BEGIN/END (i.e. in the same transaction), do you? Vadim
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