Avoid double decrement on current query counter #24922
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This commit fixes a double decrement bug on the current query counter. The double decrement arises in a situation when the fetch phase is inlined for a query that is only touching one shard. After the query phase succeeds we decrement the current query counter. If the fetch phase ultimately fails, an exception is thrown and we decrement the current query counter again in the catch block. We also add assertions that all current stats counters remain non-negative at all times.
jasontedor
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:Data Management/Stats
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LGTM |
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This bug exists since v5.3.0. Writing a test for this specific situation seems challenging yet the existing test suite HighlighterSearchIT already fails on the seed 85A57E5C8816392C with the assertions added but not the fix; with the fix the suite succeeds again. I am going to consider this sufficient unless someone has a clever idea for an easy way to write a test here. If it's agreed that writing a test for this situation is indeed not easy yet we insist on having a test, I would lean towards it being done in a follow-up as we've started to see a few reports of this issue and we should not hold a fix up. |
jasontedor
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May 27, 2017
This commit fixes a double decrement bug on the current query counter. The double decrement arises in a situation when the fetch phase is inlined for a query that is only touching one shard. After the query phase succeeds we decrement the current query counter. If the fetch phase ultimately fails, an exception is thrown and we decrement the current query counter again in the catch block. We also add assertions that all current stats counters remain non-negative at all times. Relates #24922
jasontedor
added a commit
that referenced
this pull request
May 27, 2017
This commit fixes a double decrement bug on the current query counter. The double decrement arises in a situation when the fetch phase is inlined for a query that is only touching one shard. After the query phase succeeds we decrement the current query counter. If the fetch phase ultimately fails, an exception is thrown and we decrement the current query counter again in the catch block. We also add assertions that all current stats counters remain non-negative at all times. Relates #24922
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This commit fixes a double decrement bug on the current query counter. The double decrement arises in a situation when the fetch phase is inlined for a query that is only touching one shard. After the query phase succeeds we decrement the current query counter. If the fetch phase ultimately fails, an exception is thrown and we decrement the current query counter again in the catch block. We also add assertions that all current stats counters remain non-negative at all times.
Relates #22996, closes #24872