Re: Re: 9.4-1207 behaves differently with server side prepared statements compared to 9.2-1102

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От Christian Bjørnbak
Тема Re: Re: 9.4-1207 behaves differently with server side prepared statements compared to 9.2-1102
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Msg-id CAAQEOtxyXLt-asBtYE8GY-+MjdeOhp=1o+0YVOqmLjxD4EzsgQ@mail.gmail.com
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Ответ на Re: Re: 9.4-1207 behaves differently with server side prepared statements compared to 9.2-1102  (Vladimir Sitnikov <sitnikov.vladimir@gmail.com>)
Ответы Re: Re: 9.4-1207 behaves differently with server side prepared statements compared to 9.2-1102  (Dave Cramer <pg@fastcrypt.com>)
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@Vladimir but if 1202+ has become smarter than 1102 and reuse prepared statements more often how come Thomas experience the 1207 to be magnitudes slower?

Shouldn't it be the other way around?



Med venlig hilsen / Kind regards,

Christian Bjørnbak

Chefudvikler / Lead Developer
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2016-01-11 14:05 GMT+01:00 Vladimir Sitnikov <sitnikov.vladimir@gmail.com>:
The difference is as follows: 1202 can cache across statement.close()
calls. 1201 can't do that.

In other words, to use server-prepared statements in previous
versions, you had to reuse the *same* PreparedStatement *object* again
and again. As soon as you issue .close() you lose your shiny
server-prepared statement.

Typical applications are written in a form of
PreparedStatement ps = con.prepareStatement(sql);
ps.excuteQuery();
ps.close();

In other words, almost always developers just recreate
PreparedStatement and close it.
The improvement of 1202 was to identify such patterns and use
server-prepared statement in such cases as well.
Vladimir


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