pg_backend_memory_contexts
A view displaying the memory context usage of the server process attached to the current session
This entry relates to a PostgreSQL feature which is part of PostgreSQL 14, due to be released in late 2021.
pg_backend_memory_contexts is a system catalogue view displaying the memory context usage of the server process attached to the current session. This provides an accessible method for examining memory usage in individual backends without needing to attatch a debugger.
pg_backend_memory_contexts was added in PostgreSQL 14 .
Definition by PostgreSQL version
pg_backend_memory_contexts (PostgreSQL 15)
View "pg_catalog.pg_backend_memory_contexts"
Column | Type | Collation | Nullable | Default
---------------+---------+-----------+----------+---------
name | text | | |
ident | text | | |
parent | text | | |
level | integer | | |
total_bytes | bigint | | |
total_nblocks | bigint | | |
free_bytes | bigint | | |
free_chunks | bigint | | |
used_bytes | bigint | | |
Documentation: pg_backend_memory_contexts
pg_backend_memory_contexts (PostgreSQL 14)
View "pg_catalog.pg_backend_memory_contexts"
Column | Type | Collation | Nullable | Default
---------------+---------+-----------+----------+---------
name | text | | |
ident | text | | |
parent | text | | |
level | integer | | |
total_bytes | bigint | | |
total_nblocks | bigint | | |
free_bytes | bigint | | |
free_chunks | bigint | | |
used_bytes | bigint | | |
Documentation: pg_backend_memory_contexts
Change history
- PostgreSQL 14
- added (commit 3e98c0ba); discussion thread: Creating a function for exposing memory usage of backend process
Examples
postgres=# SELECT name, parent, level, total_bytes, total_nblocks, free_bytes, free_chunks, used_bytes
FROM pg_backend_memory_contexts WHERE name != 'index info';
name | parent | level | total_bytes | total_nblocks | free_bytes | free_chunks | used_bytes
--------------------------+--------------------+-------+-------------+---------------+------------+-------------+------------
TopMemoryContext | | 0 | 68720 | 5 | 14976 | 12 | 53744
TopTransactionContext | TopMemoryContext | 1 | 8192 | 1 | 7720 | 0 | 472
Operator lookup cache | TopMemoryContext | 1 | 24576 | 2 | 10712 | 4 | 13864
Record information cache | TopMemoryContext | 1 | 8192 | 1 | 1536 | 0 | 6656
RowDescriptionContext | TopMemoryContext | 1 | 8192 | 1 | 6880 | 0 | 1312
MessageContext | TopMemoryContext | 1 | 65536 | 4 | 24144 | 0 | 41392
Operator class cache | TopMemoryContext | 1 | 8192 | 1 | 512 | 0 | 7680
smgr relation table | TopMemoryContext | 1 | 16384 | 2 | 4544 | 3 | 11840
TransactionAbortContext | TopMemoryContext | 1 | 32768 | 1 | 32504 | 0 | 264
Portal hash | TopMemoryContext | 1 | 8192 | 1 | 512 | 0 | 7680
TopPortalContext | TopMemoryContext | 1 | 8192 | 1 | 7648 | 0 | 544
PortalContext | TopPortalContext | 2 | 1024 | 1 | 568 | 0 | 456
ExecutorState | PortalContext | 3 | 49216 | 4 | 13040 | 3 | 36176
printtup | ExecutorState | 4 | 8192 | 1 | 7928 | 0 | 264
Table function arguments | ExecutorState | 4 | 8192 | 1 | 7872 | 0 | 320
ExprContext | ExecutorState | 4 | 8192 | 1 | 3336 | 0 | 4856
Relcache by OID | TopMemoryContext | 1 | 16384 | 2 | 3424 | 3 | 12960
CacheMemoryContext | TopMemoryContext | 1 | 524288 | 7 | 104416 | 0 | 419872
relation rules | CacheMemoryContext | 2 | 8192 | 4 | 464 | 0 | 7728
WAL record construction | TopMemoryContext | 1 | 49776 | 2 | 6344 | 0 | 43432
PrivateRefCount | TopMemoryContext | 1 | 8192 | 1 | 2584 | 0 | 5608
MdSmgr | TopMemoryContext | 1 | 8192 | 1 | 7864 | 0 | 328
LOCALLOCK hash | TopMemoryContext | 1 | 8192 | 1 | 512 | 0 | 7680
Timezones | TopMemoryContext | 1 | 104128 | 2 | 2584 | 0 | 101544
ErrorContext | TopMemoryContext | 1 | 8192 | 1 | 7928 | 5 | 264
(25 rows)
References
- PostgreSQL 14 documentation: pg_backend_memory_contexts