624542 - probably faster queries for username, collection, MAX(modified) [python]

Status: VERIFIED WORKSFORME

(Cloud Services Graveyard :: Server: Sync, enhancement)

Description

[Tarek Ziadé (:tarek)]

We need to check that Python uses the same query than PHP see bug 606018

Comment 1

[Toby Elliott [:telliott]]

Now that loadtesting infra is rounding into shape, we should bench

SELECT wbo_a.modified FROM %(wbo)s AS wbo_a, %(wbo)s WHERE wbo_a.username=%(wbo)s.username AND wbo_a.collection=%(wbo)s.collection ORDER BY wbo_a.username DESC, wbo_a.collection DESC, wbo_a.modified DESC LIMIT 1

vs

SELECT max(modified) from %(wbo)s where username = :username and collection = :collection

Comment 2

[Tarek Ziadé (:tarek)]

it's been months - can I close this bug or is it still relevant ?

Comment 3

[Ryan Kelly [:rfkelly]]

Since we mostly use memcache for dealing with the timestamps in production, I'm not sure there's much value in micro-optimizing this query.

FWIW, we are currently using the "SELECT MAX(modified)" variant from above, but all code paths that would execute it appear to hit memcache in production.  I'm happy to leave it at that unless Ops feel this could use further work.