Re: pgsql: Improve autovacuum logging for aggressive and anti-wraparound ru

On Fri, Oct 05, 2018 at 12:16:03PM +0900, Michael Paquier wrote:
> So, I have come back to this stuff, and finished with the attached
> instead, so as the assertion is in a single place. I find that
> clearer. The comments have also been improved. Thoughts?

And so... I have been looking at committing this thing, and while
testing in-depth I have been able to trigger a case where an autovacuum
has been able to be not aggressive but anti-wraparound, which is exactly
what should not be possible, no? I have simply created an instance with
autovacuum_freeze_max_age = 200000, then ran pgbench with
autovacuum_freeze_table_age=200000 set for each table, and also ran
installcheck-world in parallel. This has been able to trigger the
assertion pretty quickly.

Here is the stack trace:
#2 0x000055e1a12ef87b in ExceptionalCondition
(conditionName=0x55e1a14b45c8 "!((params->is_wraparound &&
aggressive) || !params->is_wraparound)",
errorType=0x55e1a14b459d "FailedAssertion", fileName=0x55e1a14b4590
"vacuumlazy.c", lineNumber=254) at assert.c:54
#3 0x000055e1a0f6c6ad in lazy_vacuum_rel (onerel=0x7f163e7ea710,
options=65, params=0x55e1a2eeba70, bstrategy=0x55e1a2f5c1a0) at
vacuumlazy.c:253
#4 0x000055e1a0f6c217 in vacuum_rel (relid=1260,
relation=0x55e1a2f5d748, options=65, params=0x55e1a2eeba70) at
vacuum.c:1714
#5 0x000055e1a0f6a3ac in vacuum (options=65, relations=0x55e1a2f2f050,
params=0x55e1a2eeba70, bstrategy=0x55e1a2f5c1a0, isTopLevel=true) at
vacuum.c:340
#6 0x000055e1a10c1ddd in autovacuum_do_vac_analyze
(tab=0x55e1a2eeba68, bstrategy=0x55e1a2f5c1a0) at autovacuum.c:3121
#7 0x000055e1a10c0e19 in do_autovacuum () at autovacuum.c:2476

$2 = {spcNode = 1664, dbNode = 0, relNode = 1260}
(gdb) p onerel->rd_node.relNode
$3 = 1260
(gdb) p params->is_wraparound
$4 = true
(gdb) p aggressive
$5 = false

I still have the core file, the binaries and the data folder, so it's
not a problem to dig into it.
--
Michael