Re: How to use full-text search URL parser to filter query results bydomain name?

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От Michel Pelletier
Тема Re: How to use full-text search URL parser to filter query results bydomain name?
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Msg-id CACxu=vKr-1TNxmQrGx0uw=baJior2-nr7-X-bNN8VTDyLMGtfg@mail.gmail.com
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Ответ на Re: How to use full-text search URL parser to filter query results bydomain name?  (Jess Wren <jess.wren@interference.cc>)
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On Wed, Apr 10, 2019 at 1:58 AM Jess Wren <jess.wren@interference.cc> wrote:
                                       ->  Parallel Seq Scan on links  (cost=0.00..4554.40 rows=75740 width=112)
                                       ->  Function Scan on ts_parse  (cost=0.00..12.50 rows=5 width=32)
                                             Filter: (tokid = 6)
(23 rows)


I am wondering if there is a more efficient way to do things? Some people on IRC mentioned that it might be better to declare a scalar function to return the host from ts_parse instead of the LATERAL query ... but I couldn't figure out how to do that, or if it was even preferable to the above from a performance standpoint ... any ideas on how I could improve the above.


May try indexing the parsed expression to avoid the seq scan on links, something like:

create index on links (ts_parse('default', target));
 
and then run the explain (or explain analyze) to see if that improves things.  Certainly as the links table gets bigger this should help.


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