5da8bf8bbb
There is no advantage to attempting deduplication for a unique index during CREATE INDEX, since there cannot possibly be any duplicates. Doing so wastes cycles due to unnecessary copying. Make sure that we avoid it consistently. We already avoided unique index deduplication in the case where there were some spool2 tuples to merge. That didn't account for the fact that spool2 is removed early/unset in the common case where it has no tuples that need to be merged (i.e. it failed to account for the "spool2 turns out to be unnecessary" optimization in _bt_spools_heapscan()). Oversight in commit 0d861bbb, which added nbtree deduplication Backpatch: 13-, where nbtree deduplication was introduced.
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/.