- |
-
-
pg_get_process_memory_contexts-
-
pg_get_process_memory_contexts (
pid integer,
summary boolean,
timeout float )
- setof record
-
num_agg_contexts integer,
-
stats_timestamp timestamptz )
-
- This function handles requests to display the memory contexts of a
-
PostgreSQL process with the specified
- process ID. The function can be used to send requests to backends as
- well as auxiliary processes.
-
- The returned record contains extended statistics per each memory
- context:
-
-
-
name - The name of the memory context.
-
-
-
-
ident - Memory context ID (if any).
-
-
-
-
type - The type of memory context, possible
- values are: AllocSet, Generation, Slab and Bump.
-
-
-
-
path - Memory contexts are organized in a
- tree model with TopMemoryContext as the root, and all other memory
- contexts as nodes in the tree. The
path- displays the path from the root to the current memory context. The
- path is limited to 100 children per node, which each node limited
- to a max depth of 100, to preserve memory during reporting. The
- printed path will also be limited to 100 nodes counting from the
- TopMemoryContext.
-
-
-
-
level - The level in the tree of the current
- memory context.
-
-
-
-
total_bytes - The total number of bytes
- allocated to this memory context.
-
-
-
-
total_nblocks - The total number of blocks
- used for the allocated memory.
-
-
-
-
free_bytes - The amount of free memory in
- this memory context.
-
-
-
-
free_chunks - The number of chunks that
-
free_bytes corresponds to.
-
-
-
-
used_bytes - The total number of bytes
- currently occupied.
-
-
-
-
num_agg_contexts - The number of memory
- contexts aggregated in the displayed statistics.
-
-
-
-
stats_timestamp - When the statistics were
- extracted from the process.
-
-
-
-
- When
summary is
true, statistics
- for memory contexts at levels 1 and 2 are displayed, with level 1
- representing the root node (i.e., TopMemoryContext).
- Statistics for contexts on level 2 and below are aggregates of all
- child contexts' statistics, where num_agg_contexts
- indicate the number aggregated child contexts. When
- the num_agg_contexts value is 1,
- indicating that individual statistics are being displayed.
-
- Busy processes can delay reporting memory context statistics,
-
timeout specifies the number of seconds
- to wait for updated statistics.
timeout can be
- specified in fractions of a second.
-
- After receiving memory context statistics from the target process, it
- returns the results as one row per context. If all the contexts don't
- fit within the pre-determined size limit, the remaining context
- statistics are aggregated and a cumulative total is displayed. The
- num_agg_contexts column indicates the number of
- contexts aggregated in the displayed statistics. When
- num_agg_contexts is 1 it means
- that the context statistics are displayed separately.
-
-
-
|
because it may generate a large number of log messages.
- pg_get_process_memory_contexts can be used to request
- memory contexts statistics of any
PostgreSQL- process. For example:
-postgres=# SELECT * FROM pg_get_process_memory_contexts(
- (SELECT pid FROM pg_stat_activity
- WHERE backend_type = 'checkpointer'),
- false, 0.5) LIMIT 1;
--[ RECORD 1 ]----+------------------------------
-name | TopMemoryContext
-ident |
-type | AllocSet
-path | {1}
-level | 1
-total_bytes | 90304
-total_nblocks | 3
-free_bytes | 2880
-free_chunks | 1
-used_bytes | 87424
-num_agg_contexts | 1
-stats_timestamp | 2025-03-24 13:55:47.796698+01
-
-
- While pg_get_process_memory_contexts can be used to
- query memory contexts of the local backend,
- pg_backend_memory_contexts
- (see for more details)
- will be less resource intensive when only the local backend is of interest.
-
-
-
-
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