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If we copy data-modifying CTEs from the original query to a replacement query (from a DO INSTEAD rule), we must set hasModifyingCTE properly in the replacement query. Failure to do this can cause various unpleasantness, such as unsafe usage of parallel plans. The code also neglected to propagate hasRecursive, though that's only cosmetic at the moment. A difficulty arises if the rule action is an INSERT...SELECT. We attach the original query's RTEs and CTEs to the sub-SELECT Query, but data-modifying CTEs are only allowed to appear in the topmost Query. For the moment, throw an error in such cases. It would probably be possible to avoid this error by attaching the CTEs to the top INSERT Query instead; but that would require a bunch of new code to adjust ctelevelsup references. Given the narrowness of the use-case, and the need to back-patch this fix, it does not seem worth the trouble for now. We can revisit this if we get field complaints. Per report from Greg Nancarrow. Back-patch to all supported branches. (The test case added here does not fail before v10, but there are plenty of places checking top-level hasModifyingCTE in 9.6, so I have no doubt that this code change is necessary there too.) Greg Nancarrow and Tom Lane Discussion: https://postgr.es/m/CAJcOf-f68DT=26YAMz_i0+Au3TcLO5oiHY5=fL6Sfuits6r+_w@mail.gmail.com Discussion: https://postgr.es/m/CAJcOf-fAdj=nDKMsRhQzndm-O13NY4dL6xGcEvdX5Xvbbi0V7g@mail.gmail.com |
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Makefile | ||
rewriteDefine.c | ||
rewriteHandler.c | ||
rewriteManip.c | ||
rewriteRemove.c | ||
rewriteSearchCycle.c | ||
rewriteSupport.c | ||
rowsecurity.c |