2017-10-08 18:44 GMT+02:00 Andres Freund <and...@anarazel.de>: > Hi, > > On 2017-10-08 18:36:23 +0200, Pavel Stehule wrote: > > 2. Lot of used tables are pretty wide - 60, 120, .. columns > > > > Now, I am doing profiling, and I see so most time is related to > > > > ExecTypeFromTLInternal(List *targetList, bool hasoid, bool skipjunk) > > Yea, that's known - I've complained about this a couple times. You could > try whether the following master branch helps: > https://git.postgresql.org/gitweb/?p=users/andresfreund/ > postgres.git;a=shortlog;h=refs/heads/simple_statement_perf > > That's just micro-optimization though, not a more fundamental > solution. But for me it yields pretty nice speedups for cases with long > tlists. > > it is just this patch
HeapTuple tup; Form_pg_type typTup; + if (typid < FirstBootstrapObjectId) + break; + tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid)); if (!HeapTupleIsValid(tup)) elog(ERROR, "cache lookup failed for type %u", typid); ? > > > This function is executed in exec init time - in this case pretty often. > > Although there are used few columns from the table, the target list is > > build for columns (maybe it is bug) > > It's probably just the physical tlist "optimization". > > > > 2. If is not possible to reduce the number of fields of target list, is > > possible to store tupledesc template to plan? > > We should do that, but it's not a small change. > > Greetings, > > Andres Freund >