Re: Bug in VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL

On 6 September 2016 at 11:30, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
> In vacuumlazy.c, VACUUM_TRUNCATE_LOCK_WAIT_INTERVAL is described as
> being in ms on line 85, yet it is used on line 1759 in a call to
> pg_usleep, so is treated as microseconds rather than milliseconds.
>
> As a result, the timeout during lazy_truncate_heap() is actually only
> 5ms long, not 5s long.
>
> So this looks to me like a bug, patch attached, for back-patching to 9.1
> vacuum_lock_wait_ms.v1,patch
>
> Objections?

I'm inclined to backpatch this for 9.6 only, unless I hear more.

For earlier releases this will suddenly make VACUUMs take 5 secs where
they used to take 50ms, which could be a big surprise for some people
running database wide VACUUMs.

--
Simon Riggs http://www.2ndQuadrant.com/
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