The following “parameters” are read-only.
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.
Most of them are determined when PostgreSQL
is compiled or when it is installed.
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 by block_size
. See Section 20.4 for information.
data_checksums
(boolean
)
#Reports whether data checksums are enabled for this cluster. See data checksums for more information.
data_encryption
(boolean
)
#Reports whether data encryption is enabled for this cluster. See Chapter 33 for more information.
data_directory_mode
(integer
)
#
On Unix systems this parameter reports the permissions the data
directory (defined by data_directory)
had at server startup.
(On Microsoft Windows this parameter will always display
0700
.) See
group access 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 the configure
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. As of PostgreSQL 10,
this is always on
.
in_hot_standby
(boolean
)
#
Reports whether the server is currently in hot standby mode. When
this is on
, all transactions are forced to be
read-only. Within a session, this can change only if the server is
promoted to be primary. See Section 27.4 for more
information.
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 of NAMEDATALEN
is
64; therefore the default
max_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 to segment_size
multiplied by
block_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.
shared_memory_size
(integer
)
#Reports the size of the main shared memory area, rounded up to the nearest megabyte.
shared_memory_size_in_huge_pages
(integer
)
#
Reports the number of huge pages that are needed for the main shared
memory area based on the specified huge_page_size.
If huge pages are not supported, this will be -1
.
This setting is supported only on Linux. It
is always set to -1
on other platforms. For more
details about using huge pages on Linux, see
Section 19.4.5.
ssl_library
(string
)
#
Reports the name of the SSL library that this
PostgreSQL server was built with (even if
SSL is not currently configured or in use on this instance), for
example OpenSSL
, or an empty string if none.
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 size of write ahead log segments. The default value is 16MB. See Section 30.5 for more information.