Tomas Vondra <t...@fuzzy.cz> wrote: > On 5.4.2012 15:44, superman0920 wrote: >> Today I install PG and MySQL at a Server. I insert 850000 rows >> record to each db. >> I execute "select count(*) from poi_all_new" at two db. >> MySQL takes 0.9s >> PG takes 364s > Are you sure the comparison was fair, i.e. both machines > containing the same amount of data (not number of rows, amount of > data), configured properly etc.? Don't forget the "hint bits" issue -- if the count(*) was run immediately after the load (without a chance for autovacuum to get in there), all the data was re-written in place to save hint information. I remember how confusing that was for me the first time I saw it. It's very easy to get a false impression of overall PostgreSQL performance from that type of test, and it's the sort of test a lot of people will do on an ad hoc basis. -Kevin
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