The following "parameters" are read-only, and are determined when PostgreSQL is compiled or when it is installed. As such, they have been excluded from the sample postgresql.conf
file. These options report various aspects of PostgreSQL behavior that might be of interest to certain applications, particularly administrative front-ends.
-
block_size
(integer
) -
Reports the size of a disk block. It is determined by the value of
BLCKSZ
when building the server. The default value is 8192 bytes. The meaning of some configuration variables (such as shared_buffers) is influenced byblock_size
. See Section 19.4 for information. -
data_checksums
(boolean
) -
Reports whether data checksums are enabled for this cluster. See data checksums for more information.
-
debug_assertions
(boolean
) -
Reports whether PostgreSQL has been built with assertions enabled. That is the case if the macro
USE_ASSERT_CHECKING
is defined when PostgreSQL is built (accomplished e.g. by theconfigure
option--enable-cassert
). By default PostgreSQL is built without assertions. -
integer_datetimes
(boolean
) -
Reports whether PostgreSQL was built with support for 64-bit-integer dates and times. This can be disabled by configuring with
--disable-integer-datetimes
when building PostgreSQL. The default value ison
. -
lc_collate
(string
) -
Reports the locale in which sorting of textual data is done. See Section 23.1 for more information. This value is determined when a database is created.
-
lc_ctype
(string
) -
Reports the locale that determines character classifications. See Section 23.1 for more information. This value is determined when a database is created. Ordinarily this will be the same as
lc_collate
, but for special applications it might be set differently. -
max_function_args
(integer
) -
Reports the maximum number of function arguments. It is determined by the value of
FUNC_MAX_ARGS
when building the server. The default value is 100 arguments. -
max_identifier_length
(integer
) -
Reports the maximum identifier length. It is determined as one less than the value of
NAMEDATALEN
when building the server. The default value ofNAMEDATALEN
is 64; therefore the defaultmax_identifier_length
is 63 bytes, which can be less than 63 characters when using multibyte encodings. -
max_index_keys
(integer
) -
Reports the maximum number of index keys. It is determined by the value of
INDEX_MAX_KEYS
when building the server. The default value is 32 keys. -
segment_size
(integer
) -
Reports the number of blocks (pages) that can be stored within a file segment. It is determined by the value of
RELSEG_SIZE
when building the server. The maximum size of a segment file in bytes is equal tosegment_size
multiplied byblock_size
; by default this is 1GB. -
server_encoding
(string
) -
Reports the database encoding (character set). It is determined when the database is created. Ordinarily, clients need only be concerned with the value of client_encoding.
-
server_version
(string
) -
Reports the version number of the server. It is determined by the value of
PG_VERSION
when building the server. -
server_version_num
(integer
) -
Reports the version number of the server as an integer. It is determined by the value of
PG_VERSION_NUM
when building the server. -
wal_block_size
(integer
) -
Reports the size of a WAL disk block. It is determined by the value of
XLOG_BLCKSZ
when building the server. The default value is 8192 bytes. -
wal_segment_size
(integer
) -
Reports the number of blocks (pages) in a WAL segment file. The total size of a WAL segment file in bytes is equal to
wal_segment_size
multiplied bywal_block_size
; by default this is 16MB. See Section 30.4 for more information.
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