db632fbca3
959d00e9d added the ability to make use of an Append node instead of a MergeAppend when we wanted to perform a scan of a partitioned table and the required sort order was the same as the partitioned keys and the partitioned table was defined in such a way that earlier partitions were guaranteed to only contain lower-order values than later partitions. However, previously we didn't allow these ordered partition scans for LIST partitioned table when there were any partitions that allowed multiple Datums. This was a very cheap check to make and we could likely have done a little better by checking if there were interleaved partitions, but at the time we didn't have visibility about which partitions were pruned, so we still may have disallowed cases where all interleaved partitions were pruned. Since 475dbd0b7, we now have knowledge of pruned partitions, we can do a much better job inside partitions_are_ordered(). Here we pass which partitions survived partition pruning into partitions_are_ordered() and, for LIST partitioning, have it check to see if any live partitions exist that are also in the new "interleaved_parts" field defined in PartitionBoundInfo. For RANGE partitioning we can relax the code which caused the partitions to be unordered if a DEFAULT partition existed. Since we now know which partitions were pruned, partitions_are_ordered() now returns true when the DEFAULT partition was pruned. Reviewed-by: Amit Langote, Zhihong Yu Discussion: https://postgr.es/m/CAApHDvrdoN_sXU52i=QDXe2k3WAo=EVry29r2+Tq2WYcn2xhEA@mail.gmail.com
PostgreSQL Database Management System ===================================== This directory contains the source code distribution of the PostgreSQL database management system. PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings. PostgreSQL has many language interfaces, many of which are listed here: https://www.postgresql.org/download/ See the file INSTALL for instructions on how to build and install PostgreSQL. That file also lists supported operating systems and hardware platforms and contains information regarding any other software packages that are required to build or run the PostgreSQL system. Copyright and license information can be found in the file COPYRIGHT. A comprehensive documentation set is included in this distribution; it can be read as described in the installation instructions. The latest version of this software may be obtained at https://www.postgresql.org/download/. For more information look at our web site located at https://www.postgresql.org/.