mirror of
https://github.com/postgres/postgres.git
synced 2025-06-05 00:02:04 -04:00
1b0d9aa4f7
Here we make a series of improvements to the generation memory allocator, namely: 1. Allow generation contexts to have a minimum, initial and maximum block sizes. The standard allocator allows this already but when the generation context was added, it only allowed fixed-sized blocks. The problem with fixed-sized blocks is that it's difficult to choose how large to make the blocks. If the chosen size is too small then we'd end up with a large number of blocks and a large number of malloc calls. If the block size is made too large, then memory is wasted. 2. Add support for "keeper" blocks. This is a special block that is allocated along with the context itself but is never freed. Instead, when the last chunk in the keeper block is freed, we simply mark the block as empty to allow new allocations to make use of it. 3. Add facility to "recycle" newly empty blocks instead of freeing them and having to later malloc an entire new block again. We do this by recording a single GenerationBlock which has become empty of any chunks. When we run out of space in the current block, we check to see if there is a "freeblock" and use that if it contains enough space for the allocation. Author: David Rowley, Tomas Vondra Reviewed-by: Andy Fan Discussion: https://postgr.es/m/d987fd54-01f8-0f73-af6c-519f799a0ab8@enterprisedb.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/.