CODEWITHSUNDEEP
postgresqlsql-server-2008
Max Pinto
Max Pinto

Reputation: 1483

Postgresql Linked Server Query very Slow

i have this problem:

Making queries over linked server to postgresql is very slow, very, very slow, for example:

if i run in pgAdmin this query:

select max(oldmedicionid) from tl.tlinputtable

it returns the max result in just: 246 msec

But if i run that over linked server (using sqlserver 2008), i create the dblink using an odbc to postgresql, so if i run this:

select MAX(oldmedicionid) from LINKPDATL.PDATL.tl.tlinputtable

the query give me result in 1 minute or more sometimes...

What could be my problema?, i think is not with my postgresql database, is something like the dblink is very slow,

How can i improve the performance?

Upvotes: 1

Views: 2252

Answers (1)

Robins Tharakan
Robins Tharakan

Reputation: 2483

Identification: There are good chances that the aggregation MAX(x) in the ODBC method is being done at the client side (not at the server side). This can easily be cross-checked by seeing that doubling the row-count would approximately double the Query time as well.

Resolution: If this is among a few corner cases, you could create a VIEW that computes this on the Postgres server-side, and the ODBC pick the aggregated value.

Upvotes: 4

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