log_temp_files makes a log entry when a temporary file is deleted. Temporary file deletion is usually organized by the resource owner mechanism. So usually it happens at the end of a query. But when the query is run through a cursor, it happens whenever the cursor is closed. So you might get a log entry like this:
LOG: temporary file: path "base/pgsql_tmp/pgsql_tmp34451.4", size 115761152 STATEMENT: close foo; That's a bit unhelpful, but at least you can gather some context. It's even less helpful when the cursor is closed by the normal transaction end, because then you can't tell from the log message which cursor was involved: LOG: temporary file: path "base/pgsql_tmp/pgsql_tmp34451.4", size 115761152 STATEMENT: commit; But where it gets really bad is if you use an unnamed portal, for example through the JDBC driver. The unnamed portal is typically closed when the next query is run. So the temporary file log entry is in the logs associated with the next query. This can obviously lead to lots of confusion when using this to debug query performance. Thoughts on how to improve that? Perhaps we could optionally save a reference to the portal, or the query string itself, in the Vfd structure and use that to log? -- Peter Eisentraut http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
