MSQ: Nicer error when sortMerge join falls back to broadcast. #16002
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In certain cases, joins run as broadcast even when the user hinted that they wanted sortMerge. This happens when the sortMerge algorithm is unable to process the join, because it isn't a direct comparison between two fields on the LHS and RHS. When this happens, the error message from BroadcastTablesTooLargeFault is quite confusing, since it mentions that you should try sortMerge to fix it. But the user may have already configured sortMerge. This patch fixes it by having two error messages, based on whether broadcast join was used as a primary selection or as a fallback selection.
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bot
added
Area - Batch Ingestion
Area - MSQ
LakshSingla
reviewed
Feb 29, 2024
| ); | ||
| } else { | ||
| return StringUtils.format( | ||
| "Size of broadcast tables in JOIN exceeds reserved memory limit " |
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We can ask the user to "Increase the available memory" to remedy the situation.
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Yes, good point, I lost that part by accident. Added it back.
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In certain cases, joins run as broadcast even when the user hinted that they wanted sortMerge. This happens when the sortMerge algorithm is unable to process the join, because it isn't a direct comparison between two fields on the LHS and RHS.
When this happens, the error message from BroadcastTablesTooLargeFault is quite confusing, since it mentions that you should try sortMerge to fix it. But the user may have already configured sortMerge.
This patch fixes it by having two error messages, based on whether broadcast join was used as a primary selection or as a fallback selection.