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Since commit 859b3003de we only build extended statistics for individual relations, ignoring the child relations. This resolved the issue with updating catalog tuple twice, but we still tried to use the statistics when calculating estimates for the whole inheritance tree. When the relations contain very distinct data, it may produce bogus estimates. This is roughly the same issue 427c6b5b9 addressed ~15 years ago, and we fix it the same way - by ignoring extended statistics when calculating estimates for the inheritance tree as a whole. We still consider extended statistics when calculating estimates for individual child relations, of course. This may result in plan changes due to different estimates, but if the old statistics were not describing the inheritance tree particularly well it's quite likely the new plans is actually better. Report and patch by Justin Pryzby, minor fixes and cleanup by me. Backpatch all the way back to PostgreSQL 10, where extended statistics were introduced (same as 859b3003de). Author: Justin Pryzby Reported-by: Justin Pryzby Backpatch-through: 10 Discussion: https://postgr.es/m/20210923212624.GI831%40telsasoft.com
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