On 2017-08-16 14:41, gmb wrote:
Hi
For DDL purposes we make significant use of pg_catalog tables/views.
Were investigating performance issues in a typical function:
CREATE FUNCTION tableexists( s TEXT , t TEXT ) returns boolean as
$$
SELECT count(tablename) = 1 FROM pg_tables WHERE schemaname=$1 and
tablename=$2;
$$
language sql
When change the params of above function to VARCHAR (instead of TEXT),
performance improved dramatically.
We then changed params to NAME ( as per pg_tables column type ) , but
the
performance stayed more or less the same.
Can somebody explain this to me ? Is there a better way in which to
handle
these ?
(This will be implemented on most object in the catalog e.g. columns,
sequences, functions, etc )
Regards
gmb
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A wild stab in the dark: typecasting?
pg_tables returns 'name' type, not TEXT, so some sort of transformation
has to be done and that takestime.
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