#25230: Change to Query.get_count() causes big performance hit
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Reporter: dexity | Owner: (none)
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: 1.8
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 1 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 1
Easy pickings: 0 | UI/UX: 0
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Comment (by Sidharth Dusanapudi):
I'd like to take a conservative swing at this before opening a PR.
After reading #23875, #30685, and PR #16630, would a narrow fix be welcome
if it only optimizes cases where distinct() is clearly redundant for
count(), e.g. base-table-only queries with no joins, slicing, grouping,
aggregation, annotations, distinct(*fields), combinators, or extra select?
I’d leave the broader/edge cases from #16630 out of scope. I also have
local PostgreSQL/MySQL benchmark numbers for the current wide DISTINCT
subquery if useful.
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Ticket URL: <https://code.djangoproject.com/ticket/25230#comment:13>
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