Wiki / Configuration Parameters

Sets the number of concurrent storage I/O operations that PostgreSQL expects can be executed simultaneously. Raising this value will increase the number of I/O operations that any individual PostgreSQL session attempts to initiate in parallel. The allowed range is 1 to 1000, or 0 to disable issuance of asynchronous I/O requests. The default is 16. Higher values will have the most impact on higher latency storage where queries otherwise experience noticeable I/O stalls and on devices with high IOPs. Unnecessarily high values may increase I/O latency for all queries on the system. On systems with prefetch advice support, effective_io_concurrency also controls the prefetch distance. This value can be overridden for tables in a particular tablespace by setting the tablespace parameter of the same name (see ALTER TABLESPACE).

English manual coverage begins with PostgreSQL 7.4. Source history and runtime observations have their own recorded version boundaries.

boot val

16

category

Resource Usage / I/O

context

user

documented

true

enumvals

Unknown

extra desc

0 disables simultaneous requests.

lang

en

max val

1000

metadata version

18

min val

0

name

effective_io_concurrency

short desc

Number of simultaneous requests that can be handled efficiently by the disk subsystem.

source

pg-settings-source-snapshot

unit

Unknown

vartype

integer