Wiki / 配置参数

Specifies the amount of memory to be used by internal sort operations and hash tables before switching to temporary disk files. The value is specified in kilobytes, and defaults to 1024 kilobytes (1 MB). Note that for a complex query, several sort or hash operations might be running in parallel; each one will be allowed to use as much memory as this value specifies before it starts to put data into temporary files. Also, several running sessions could be doing sort operations simultaneously. So the total memory used could be many times the value of sort_mem. Sort operations are used by ORDER BY, merge joins, and CREATE INDEX. Hash tables are used in hash joins, hash-based aggregation, and hash-based processing of IN subqueries. Because CREATE INDEX is used when restoring a database, increasing sort_mem before doing a large restore operation can improve performance.

英文手册覆盖始于 PostgreSQL 7.4. 来源历史与运行验证各自保留独立版本边界。

此版本暂无所选语言的定义，以下显示原始英文内容。

boot val

未知

category

Memory

context

未知

documented

true

enumvals

未知

extra desc

未知

lang

en

max val

未知

metadata version

未知

min val

未知

name

sort_mem

short desc

未知

source

english-manual

unit

未知

vartype

integer