c00c3249e3
These functions have been looking up type info for every row they process. Instead of doing that we only look them up the first time through and stash the information in the aggregate state object. Affects json_agg, json_object_agg, jsonb_agg and jsonb_object_agg. There is plenty more work to do in making these more efficient, especially the jsonb functions, but this is a virtually cost free improvement that can be done right away. Backpatch to 9.5 where the jsonb variants were 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: 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/.