2f5b8eb5a2
heap.c and relcache.c contained nearly identical copies of logic to insert OIDs into an OID list while preserving the list's OID ordering (and rejecting duplicates, in one case but not the other). The comments argue that this is faster than qsort for small numbers of OIDs, which is at best unproven, and seems even less likely to be true now that lappend_cell_oid has to move data around. In any case it's ugly and hard-to-follow code, and if we do have a lot of OIDs to consider, it's O(N^2). Hence, replace with simply lappend'ing OIDs to a List, then list_sort the completed List, then remove adjacent duplicates if necessary. This is demonstrably O(N log N) and it's much simpler for the callers. It's possible that this would be somewhat inefficient if there were a very large number of duplicates, but that seems unlikely in the existing usage. This adds list_deduplicate_oid and list_oid_cmp infrastructure to list.c. I didn't bother with equivalent functionality for integer or pointer Lists, but such could always be added later if we find a use for it. Discussion: https://postgr.es/m/26193.1563228600@sss.pgh.pa.us
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/.