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Fix recompilation of regexps during backtracking in the parser #61543
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robot-ch-test-poll2
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Pull request with some performance improvements
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Mar 18, 2024
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serxa
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Mar 18, 2024
I cannot explain the difference that the Performance test has shown and assume they are irrelevant. |
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Mar 21, 2024
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pr-performance
Pull request with some performance improvements
pr-synced-to-cloud
The PR is synced to the cloud repo
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Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):
If a query with a syntax error contained COLUMNS matcher with a regular expression, the regular expression was compiled each time during the parser's backtracking, instead of being compiled once. This was a fundamental error. The compiled regexp was put to AST. But the letter A in AST means "abstract" which means it should not contain heavyweight objects. Parts of AST can be created and discarded during parsing, including a large number of backtracking. This leads to slowness on the parsing side and consequently allows DoS by a readonly user. But the main problem is that it prevents progress in fuzzers.