Opened 14 years ago

Closed 13 years ago

Last modified 12 years ago

#15580 closed Bug (fixed)

DB cache backend uses LIMIT / OFFSET query for culling

Reported by: Erin Kelly Owned by: nobody
Component: Core (Cache system) Version: dev
Severity: Normal Keywords: oracle
Cc: Triage Stage: Accepted
Has patch: yes Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no

Description

As a result, the DB cache backend cannot safely be used with Oracle.

Attachments (1)

15580.patch​ (2.5 KB ) - added by Erin Kelly 14 years ago.

Download all attachments as: .zip

Change History (8)

comment:1 by Erin Kelly, 14 years ago

For Oracle, the existing query should probably be replaced with:

SELECT cache_key
FROM (SELECT cache_key, rank() OVER (ORDER BY cache_key) AS rank FROM  %s)
WHER rank = %%s

comment:2 by Russell Keith-Magee, 14 years ago

Triage Stage: Unreviewed → Accepted

This is obviously a limitation -- however, it's not clear to me what the resolution should be. I really don't want to replace the internals of the DB cache backend with the ORM just so that we can get LIMIT and OFFSET support for Oracle. We may just need to introduce an 'Oracle' DB backend, and specialize that one call.

comment:3 by Luke Plant, 14 years ago

Type: → Bug

comment:4 by Luke Plant, 14 years ago

Severity: → Normal

by Erin Kelly, 14 years ago

Attachment: 15580.patch​ added

comment:5 by Erin Kelly, 14 years ago

Has patch: set

I've added a patch that pushes out this one query to connection.ops rather than to the ORM. I don't think tests are needed since this is already caught by regressiontests.cache.tests.DBCacheTests.test_cull.

Russell, please let me know if this looks okay to you.

comment:6 by Aymeric Augustin, 13 years ago

Easy pickings: unset
Resolution: → fixed
Status: new → closed
UI/UX: unset

I reported a duplicate, #16481 -- my bad -- and it was fixed at r16635, arguably in a less elegant manner.

I'm closing this as "fixed", because technically it is fixed.

I'll try to get a core developer to take a look at this patch. It could be worth reverting r16635 and applying this patch instead.

comment:7 by Anssi Kääriäinen, 12 years ago

I committed ikelly's patch in d3c2eb103f6682c029a850e60dc4cf85896b6aa2 to make the cache database backend 3rd party database friendly.

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