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

I can confirm, It really behave differently, but not for the same reason as yours.
In my case, problema is that after optimization at server side, results get different.

I always work with url parameter:

jdbc:postgresql://dbdevel:5433/mydatabase?prepareThreshold=0

When using prepareThreshold=0, I do avoid the server side prepared statements.

My be worth to give a try, since would also makes difference for you as well.

Atenciosamente,

Edson Carlos Ericksson Richter

It's not that JDBC is slower, it is the plans that are being generated are slower. I can't imagine why that would even happen. 

JDBC doesn't really change the incoming SQL

Dave Cramer

davec@postgresintl.com

www.postgresintl.com

On 11 January 2016 at 08:29, Christian Bjørnbak <cbj@touristonline.dk> wrote:

@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
TouristOnline A/S
Islands Brygge 43
2300 København S
Denmark
TLF: +45 32888230
Dir. TLF: +45 32888235

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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