On Mon, 19 Aug 2024 at 19:48, sud <suds1434@xxxxxxxxx> wrote: > In a version 15.4 postgres database, Is it possible that , if we have two big range partition tables with foreign key relationships between them, insert into the child table can cause slowness if we don't have foreign key index present in the child table? Basically it need to make sure the new row already added to parent partition table or not. Having an index on the referencing columns is only useful for DELETEs and UPDATEs affecting the foreign key column(s). For INSERTs to the referencing table, technically having indexes there would only slow down inserts due to the additional overhead of having to maintain the index, however, the overhead of having the index might be fairly minuscule when compared to performing a CASCADE UPDATE or DELETE to the referencing table when the DDL is performed on the referenced table. > And if there is any possible way(example query tracing etc) to get the underlying system queries which gets triggered as part of the main insert query? For example in above scenario, postgres must be executing some query to check if the incoming row to the child table already exists in the parent table or not? EXPLAIN ANALYZE will list the time it took to execute the foreign key trigger in the "Trigger for constraint" section. David
