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c23844212d
Convert the binary_coercible() and physically_coercible() functions from SQL to plpgsql. It's not that plpgsql is inherently better at doing queries; if you simply convert the previous single SQL query into one RETURN expression, it's no faster. The problem with the existing code is that it fools the plancache into deciding that it's worth re-planning the query every time, since constant-folding with a concrete value for $2 allows elimination of at least one sub-SELECT. In reality that's using the planner to do the equivalent of a few runtime boolean tests, causing the function to run much slower than it should. Splitting the AND/OR logic into separate plpgsql statements allows each if-expression to acquire a static plan. Also, get rid of some uses of obj_description() in favor of explicitly joining to pg_description, allowing the joins to be optimized better. (Someday we might improve the SQL-function-inlining logic enough that this happens automatically, but today is not that day.) Together, these changes reduce the runtime of the opr_sanity regression test by about a factor of two on one of my slower machines. They don't seem to help as much on a fast machine, but this should at least benefit the buildfarm. |
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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: http://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 http://www.postgresql.org/download/. For more information look at our web site located at http://www.postgresql.org/.