Re: [JDBC] 8.0.1 performance question. - Mailing list pgsql-performance

From Kris Jurka
Subject Re: [JDBC] 8.0.1 performance question.
Date
Msg-id Pine.BSO.4.56.0504041109140.4842@leary.csoft.net
Whole thread Raw
In response to 8.0.1 performance question.  (<alvin.yk@gmail.com>)
Responses Re: [JDBC] 8.0.1 performance question.
List pgsql-performance

On Tue, 5 Apr 2005 alvin.yk@gmail.com wrote:

> I see statements below being executed non-stop.  Who is triggering these
> statemetns?  Is this normal?  What am I doing wrong?
>
>
> 2005-04-04 18:05:00 CST PARSELOG:  statement: SELECT attnotnull FROM
> pg_catalog.pg_attribute WHERE attrelid = $1 AND attnum = $2
> 2005-04-04 18:05:00 CST PARSELOG:  statement: SELECT def.adsrc FROM
> pg_catalog.pg_class c JOIN pg_catalog.pg_attribute a ON
> (a.attrelid=c.oid
> ) LEFT JOIN pg_catalog.pg_attrdef def ON (a.attrelid=def.adrelid AND
> a.attnum = def.adnum) WHERE c.oid = $1 and a.attnum = $2 AND def.adsrc
> L
> IKE '%nextval(%'

These are the results of ResultSetMetaData.isNullable() and
isAutoIncrement(), which your code is apparently calling.  The results of
these calls are cached on a per ResultSet data.  We have discussed
caching them at a higher level, but couldn't find a way to know when to
flush that cache.

Kris Jurka

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