On Tue, Mar 31, 2026 at 5:04 AM Corey Huinker <[email protected]> wrote:
>> postgres_fdw side: >> >> * In fetch_remote_statistics, if we get reltuples=0 for v14 or later, >> I think we should update only the relation stats with that info, and >> avoid resorting to analyzing, for efficiency, as I proposed before. I >> modified that function (and import_fetched_statistics) that way. > > This will miss out on the case where the remote table did get analyzed once, > when empty, but now isn't empty. I realize that shouldn't happen very often, > but the cost of rowsampling a table that is empty is very low. I think that that would be the user's fault, as it's the user's responsibility to ensure that the existing stats for the remote table are up-to-date. From another perspective, not all users will be able to operate in such a way, so I'm thinking of disabling this feature by default. > I see that remote_analyze didn't make it as a part of this patch. Is that > something you'd repackaged as a follow-on patch, or are you just done with it? As just reviewing/polishing the 0001/0002 patches is a lot of work, I didn't have time to look at the remote_analyze patch. We are running out of time, so I'm afraid that I won't be able to have time for that. I modified the patch further: * Modified postgresImportStatistics to create RemoteAttributeMapping if needed. * The query executed in fetch_relstats is almost the same as the one executed in postgresGetAnalyzeInfoForForeignTable. To avoid code duplication, I modified it to use the latter query. I also changed it to use PQsendQuery, not PQsendQueryParams, for efficiency. * Modified import_spi_query_ok to get the result of an import query by using SPI_getbinval, not SPI_getvalue, for efficiency. Attached is a new version of the patch. Thanks for reviewing! Best regards, Etsuro Fujita
v18-Add-remote-statistics-fetching-to-postgres_fdw.patch
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