0070b66fef
After 0da243fed0 got committed, it was reported that in some cases the compression ratio is rather poor - particularly for custom format with narrow tables - due to writing the LZ4 header/footer for each row. This commit switches to LZ4F (LZ4 frame format), eliminating most of the overhead and greatly improving the compression ratio. This makes the compressed size about the same for plain and custom formats (just like for gzip, for example). LZ4F is now used by both compression APIs, which allowed refactoring and reusing more of the code. For consistency this also renames the LZ4File struct to LZ4State, and a number of functions are now prefixed with LZ4Stream_ (instead of LZ4File_). Patch by Georgios Kokolatos, based on report and initial patch by Justin Pryzby. Review and minor cleanups by me. Author: Georgios Kokolatos, Justin Pryzby Reported-by: Justin Pryzby Reviewed-by: Tomas Vondra Discussion: https://postgr.es/m/20230227044910.GO1653%40telsasoft.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/.