mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-12-09 08:10:09 +08:00
b071a31149
Consolidate discussion of how VACUUM places pages in the FSM for recycling by adding a new section that comes after discussion of page deletion. This structure reflects the fact that page recycling is explicitly decoupled from page deletion in Lanin & Shasha's paper. Page recycling in nbtree is an implementation of what the paper calls "the drain technique". This decoupling is an important concept for nbtree VACUUM. Searchers have to detect and recover from concurrent page deletions, but they will never have to reason about concurrent page recycling. Recycling can almost always be thought of as a low level garbage collection operation that asynchronously frees the physical space that backs a logical tree node. Almost all code need only concern itself with logical tree nodes. (Note that "logical tree node" is not currently a term of art in the nbtree code -- this all works implicitly.) This is preparation for an upcoming patch that teaches nbtree VACUUM to remember the details of pages that it deletes on the fly, in local memory. This enables the same VACUUM operation to consider placing its own deleted pages in the FSM later on, when it reaches the end of btvacuumscan(). |
||
|---|---|---|
| config | ||
| contrib | ||
| doc | ||
| src | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitattributes | ||
| .gitignore | ||
| aclocal.m4 | ||
| configure | ||
| configure.ac | ||
| COPYRIGHT | ||
| GNUmakefile.in | ||
| HISTORY | ||
| Makefile | ||
| README | ||
| README.git | ||
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/.