We have a customer complaining about the time taken by one of the application scripts while deleting older data from the log tables.
During the deletion, customer reported that he often sees the below error and because of which table size doesn’t reduce.
You should look into partitioning (implemented via inheritance) for your log table so that you can simply issue a "DROP TABLE ..."
ERROR: canceling autovacuum task
Date: 2015-03-14 04:29:19
Context: automatic analyze of table "fm_db_Server3.mmsuper.audittraillogentry"
We have the following queries in this regard:
-How often is the autovacuum task invoked by postgres
As often as it needs to - based upon changes being made to tables
-If the task gets cancelled (while we were deleting data from the database) would this task be re-invoked at a later time?
Yes
-If insertion of data into a table also impact this task?
Yes
-If we can manually schedule this task to a particular time (like off peak hours)?
Yes. You can issue "ANALYZE" (or VACUUM) manually via SQL or the PostgreSQL provided "vacuumdb" command using whatever external scheduling mechanism you have at your disposal.
