[patches] [PATCH v2 0/3] vinyl: alternative fix for tx read set bloating

Konstantin Osipov kostja at tarantool.org
Wed Mar 7 15:47:41 MSK 2018


* Vladimir Davydov <vdavydov.dev at gmail.com> [18/03/07 15:09]:

Pushed.

> When we iterate over a secondary index, we track not only the interval
> read from the secondary index, but also each tuple retrieved from the
> primary index, which results in read set bloating (see #2534).
> Originally, the problem was fixed by forcing all autocommit SELECTs to
> open a read view immediately, but that entailed a problem with the
> tuple cache - now a SELECT called outside transaction doesn't populate
> the cache at all, which affects performance (#3197).
> 
> In fact, we don't need to track tuples in primary index when we are
> scanning a secondary index, because whenever we change a tuple in the
> primary index, we update it in all secondary indexes, so tracking in a
> secondary index is enough. So this patch reverts the original fix
> (patch 1) and instead removes this extra tracking (patches 2 and 3).
> 
> https://github.com/tarantool/tarantool/issues/2534
> https://github.com/tarantool/tarantool/issues/3197
> https://github.com/tarantool/tarantool/tree/gh-2534-vy-dont-open-rv-for-select
> 

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Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.org - www.twitter.com/kostja_osipov



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