Fix REGEXP_EXTRACT to return NULL instead of empty string on no match#31
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Fix REGEXP_EXTRACT to return NULL instead of empty string on no match#31ggjh-159 wants to merge 1 commit into
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What changes are proposed in this pull request?
Override
regexp_extractto return NULL on no match instead of empty string. The Spark version passesemptyNoMatch=true, returning empty string on no match. Flink'sREGEXP_EXTRACTexpects NULL on no match. This matters forIS NOT NULLfiltering which breaks when empty string is returned instead of NULL.How was this patch tested?
Tested by running Nexmark Q21 on Gluten-Flink with 10000 events. The query uses
WHERE REGEXP_EXTRACT(url, '(&|^)channel_id=([^&]*)', 2) IS NOT NULL. Previously rows withoutchannel_idin URL were incorrectly included (REGEXP_EXTRACT returned""making IS NOT NULL always true). After this fix, those rows are correctly filtered out.Note: A companion fix in gluten-flink is also needed. See gluten-pr-12267.
related issue: gluten-issue-12266.