MDEV-39013: Fix flaky main.tmp_space_usage test#4765
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varundeepsaini wants to merge 1 commit intoMariaDB:11.8from
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MDEV-39013: Fix flaky main.tmp_space_usage test#4765varundeepsaini wants to merge 1 commit intoMariaDB:11.8from
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Thank you for your contribution! This is a preliminary review.
Mostly LGTM, but please rebase on 11.8
Reading information_schema.session_status with tmp_memory_table_size=0 forces the query's internal temp table to disk, which changes tmp_space_used as a side effect of reading it. By the time connection c1 reads the value from processlist, it sees the inflated value. Fix by temporarily setting tmp_memory_table_size high before the session_status read, same pattern already used earlier in the test (lines 72-77) for the same reason. Signed-off-by: Varun Deep Saini <varun.23bcs10048@ms.sst.scaler.com>
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LGTM. Please stand by for the final review.
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Summary
information_schema.session_statuswithtmp_memory_table_size=0forces the query's internal temp table to disk, which changestmp_space_usedas a side effect of reading it. By the time connection c1 reads the value fromprocesslist, it sees the inflated value (observed diff: exactly 16384 bytes = one InnoDB page).tmp_memory_table_sizehigh before thesession_statusread — same pattern already used earlier in the test (lines 72-77) for the same reason.Test plan
main.tmp_space_usagepasses locally (500/500 runs)