problems: slow queries with tsearch2 - Mailing list pgsql-general

From Rafa Comino
Subject problems: slow queries with tsearch2
Date
Msg-id bd8b58a40702160939j360c458et7ad727dcdfe1639a@mail.gmail.com
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Responses Re: problems: slow queries with tsearch2
List pgsql-general

Hi from Spain,

I have a problem with TSearch2,

I have a table with more than a million registers (a table of books, for example),

I made a tsearch2 index for one of my fields (the title of the books, for example),

I make queries from that table, over the tsearch2 index. Then some of my queries get too much slowly, and I don't know how to resolve it. For example:

  • Every thing is ok, but when the query get a lot of results (about 1000 register) and I use ORDER BY over other field in the query (even if I use LIMIT 10) the query gets slowly, 7 or 8 seconds. The thing is, that query gets all the results and later order those results, and that makes my query so slow. How can I resolve this.
  • When my queries have two conditions joined with AND, and each condition is made over a different tsearch2 index, the execution get first x rows from the first condition, and y rows from the second condition, later get the rows from both result set. This makes my queries slow too. How could I resolve this?.

 

(Sorry for my English, and thanks for reading me)

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