20.04.2017 16:20, Vlad Khorsun wrote: >> even in the simplest cases like "select f from t1 union select f from t2"? > This case nor simplest nor better for parallel execution than "ordinary" > "select * from t".
Union used to produce plan SORT (T1 NATURAL), SORT(T2 NATURAL). Both record streams can be fetched and sorted in parallel and then merged, right? And because of selects from different tables, they won't race on data pages. -- WBR, SD. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
