Re: Slow query plan used

Am 30.05.2017 um 10:42 schrieb Wetzel, Juergen (Juergen):

> I have a question concerning the query planner. I observe that chosen
query plan differs on length and content of a like
> search expression. We have a view combining data from two tables,
both containing same number of rows (round about 30000).
> Used PostgreSQL version is 9.3.15 on Windows. DDL of tables and view
see below.

the query is on DOCUMENTDATA, but plan and DDL for c3k_documentdata and
other tables.

> Only 130 rows out of the 30000 have ARCHIVED = 0

in this case i would suggest a partial index:

create index <indexname> on <tablename> (archived) where archived = 0;

You can also increase the statistics for the columns subject and mailContent

ALTERTABLE<tablename>ALTERCOLUMN<column_name> SETSTATISTICS=1000;

(as example, the default-value is 100)

Regards, Andreas

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