I've often wanted to know what the autovacuum worker was doing. The process title seems like the best place to get this information, but the process title tells me what database it is in, but not what table it is working on.
The attached patch demonstrates the concept of what I want. I put the code in table_recheck_autovac not because I think that is the best location, but just because it was the easiest point at which I knew how to get the table name easily before classTup gets destroyed.
Example output:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
16392 jjanes 20 0 229m 19m 6948 S 3.6 1.0 0:06.85 postgres: autovacuum worker process jjanes.public.pgbench_accounts
I never reset the process title back to the initial state of just having a database name and no table. Which I can get away with temporarily because the autovac worker never dilly-dallies between tables, it either goes to the next one, or exits. A real implementation would probably want to reset it anyway, though.
Is this functionality something we want? If so should it include explicit vacuum as well as autovac? Any opinion about where in the code base it properly belongs (which obviously depends on whether it should cover manual vacuum as well)? And does the string need to distinguish between an autovac and an autoanalyze?
Cheers,
Jeff