Marc Mamin wrote:
Hello,
- did you vacuum your tables recently ?
- What I miss in your query is a check for the rows that do not need to be udated:
AND NOT (service = b.service
AND status = b.status
AND has_notification = gateway_id NOT IN (4,101,102)
AND operator = COALESCE( b.actual_target_network_id, b.requested_target_network_id )
depending on the fraction of rows that are already up to date, the might fasten your process quite a lot...
I don't see why it would. As far as I know, the high saving in update time is done by using the indices. All the other conditions that are not on indices are all checked using a sequential scan on the rows that were brought from the index, so adding more conditions wouldn't make this a lot faster - maybe even slower because more comparisons are made.
In any case, the logic of the database is that the records that have delivered = 0 are always a subset of the records that are changed in this query, so querying on delivered=0 - which is an indexed query - actually make the above redundant.
Thanks for your response,
Herouth
