Re: creating of temporary table takes very long

Explain analyze on the select statement that is the basis for temp table
data takes forever. I turned off enable_seqscan but it did not have an
effect

________________________________

From: pgsql-performance-owner(at)postgresql(dot)org
[mailto:pgsql-performance-owner(at)postgresql(dot)org] On Behalf Of Sriram
Dandapani
Sent: Monday, April 17, 2006 11:37 AM
To: Pgsql-Performance (E-mail)
Subject: [PERFORM] creating of temporary table takes very long

create temporary table c_chkpfw_hr_tr_updates as

select * from c_chkpfw_hr_tr a

where exists(select 1 from
chkpfw_tr_hr_dimension b

WHERE a.firstoccurrence =
b.firstoccurrence

AND a.sentryid_id = b.sentryid_id

AND a.node_id = b.node_id

AND a.customerid_id =
b.customerid_id

AND coalesce(a.interface_id,0) =
coalesce(b.interface_id,0)

AND coalesce(a.source_id,0) =
coalesce(b.source_id,0)

AND coalesce(a.destination_id,0) =
coalesce(b.destination_id,0)

AND coalesce(a.sourceport_id,0) =
coalesce(b.sourceport_id,0)

AND
coalesce(a.destinationport_id,0) = coalesce(b.destinationport_id,0)

AND coalesce(a.inoutbound_id,0) =
coalesce(b.inoutbound_id,0)

AND coalesce(a.action_id,0) =
coalesce(b.action_id,0)

AND coalesce(a.protocol_id,0) =
coalesce(b.protocol_id,0)

AND coalesce(a.service_id,0) =
coalesce(b.service_id,0)

AND coalesce(a.sourcezone_id,0) =
coalesce(b.sourcezone_id,0)

AND
coalesce(a.destinationzone_id,0) = coalesce(b.destinationzone_id,0));

This takes forever (I have to cancel the statement each time)

c_chkpfw_hr_tr has about 20000 rows

chkpfw_tr_hr_dimension has 150K rows

c_chkpfw_hr_tr has same indexes as chkpfw_tr_hr_dimension

For such a small data set, this seems like a mystery. The only other
alternative I have is to use cursors which are also very slow for row
sets of 10- 15K or more.