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Prevent needless allocation of sqlite3 aggregate function context #87424

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erlend-aasland opened this issue Feb 18, 2021 · 3 comments
Closed

Prevent needless allocation of sqlite3 aggregate function context #87424

erlend-aasland opened this issue Feb 18, 2021 · 3 comments
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3.10 only security fixes stdlib Python modules in the Lib dir

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@erlend-aasland
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BPO 43258
Nosy @berkerpeksag, @serhiy-storchaka, @erlend-aasland
PRs
  • bpo-43258: Prevent needless allocation of sqlite3 aggregate context for empty queries #24569
  • bpo-43258: Fix sqlite3 UDF callback scoping #24574
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    Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

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    GitHub fields:

    assignee = None
closed_at = <Date 2021-02-19.11:59:49.384>
created_at = <Date 2021-02-18.22:21:00.100>
labels = ['library', '3.10']
title = 'Prevent needless allocation of sqlite3 aggregate function context'
updated_at = <Date 2021-02-19.11:59:49.383>
user = 'https://github.com/erlend-aasland'

    bugs.python.org fields:

    activity = <Date 2021-02-19.11:59:49.383>
actor = 'berker.peksag'
assignee = 'none'
closed = True
closed_date = <Date 2021-02-19.11:59:49.384>
closer = 'berker.peksag'
components = ['Library (Lib)']
creation = <Date 2021-02-18.22:21:00.100>
creator = 'erlendaasland'
dependencies = []
files = []
hgrepos = []
issue_num = 43258
keywords = ['patch']
message_count = 3.0
messages = ['387272', '387305', '387309']
nosy_count = 3.0
nosy_names = ['berker.peksag', 'serhiy.storchaka', 'erlendaasland']
pr_nums = ['24569', '24574']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue43258'
versions = ['Python 3.10']
    @erlend-aasland
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    If no rows match an aggregate query, _pysqlite_step_callback() is never called, and _pysqlite_final_callback() is called once. In order to prevent needless context allocation, we should pass 0 as the second argument to sqlite3_aggregate_context().

    Quoting from https://sqlite.org/c3ref/aggregate_context.html:

    Within the xFinal callback, it is customary to set N=0 in calls to sqlite3_aggregate_context(C,N) so that no pointless memory allocations occur.

    @erlend-aasland erlend-aasland added 3.10 only security fixes stdlib Python modules in the Lib dir labels Feb 18, 2021
    @berkerpeksag
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    New changeset 979b23c by Erlend Egeberg Aasland in branch 'master':
    bpo-43258: Don't allocate sqlite3 aggregate context for empty queries (GH-24569)
    979b23c

    @berkerpeksag
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    New changeset 2bb0bf4 by Erlend Egeberg Aasland in branch 'master':
    bpo-43258: Make sqlite3 callback functions static (GH-24574)
    2bb0bf4

    @ezio-melotti ezio-melotti transferred this issue from another repository Apr 10, 2022
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    @berkerpeksag @erlend-aasland