Re: Reviewing freeze map code

On 5/6/16 4:20 PM, Andres Freund wrote:
> On 2016-05-06 14:15:47 -0700, Josh berkus wrote:
>> For the serious testing, does anyone have a good technique for creating
>> loads which would stress-test vacuum freezing?  It's hard for me to come
>> up with anything which wouldn't be very time-and-resource intensive
>> (like running at 10,000 TPS for a week).
>
> I've changed the limits for freezing options a while back, so you can
> now set autovacuum_freeze_max as low as 100000 (best set
> vacuum_freeze_table_age accordingly).  You'll have to come up with a
> workload that doesn't overwrite all data continuously (otherwise
> there'll never be old rows), but otherwise it should now be fairly easy
> to test that kind of scenario.

There's also been a tool for forcibly advancing XID floating around for 
quite some time. Using that could have the added benefit of verifying 
anti-wrap still works correctly. (Might be worth testing mxid wrap too...)
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