MOT Monitoring

All syntax for monitoring of PG-based FDW tables is supported. This includes Table or Index sizes (as described below). In addition, special functions exist for monitoring MOT memory consumption, including MOT Global Memory, MOT Local Memory and a single client session.

Table and Index Sizes

The size of tables and indexes can be monitored by querying pg_relation_size.

For example

Data Size

select pg_relation_size('customer');

Index

select pg_relation_size('customer_pkey');

MOT GLOBAL Memory Details

Check the size of MOT global memory, which includes primarily the data and indexes.

select * from mot_global_memory_detail();

Result –

numa_node  | reserved_size        | used_size
----------------+----------------+-------------
-1            | 194716368896      | 25908215808
0             | 446693376         | 446693376
1             | 452984832         | 452984832
2             | 452984832         | 452984832
3             | 452984832         | 452984832
4             | 452984832         | 452984832
5             | 364904448         | 364904448
6             | 301989888         | 301989888
7             | 301989888         | 301989888

Where –

-1 is the total memory.
0..7 are NUMA memory nodes.

MOT LOCAL Memory Details

Check the size of MOT local memory, which includes session memory.

select * from mot_local_memory_detail();

Result –

numa_node  | reserved_size      | used_size   
----------------+----------------+-------------
-1            | 144703488       | 144703488
0             | 25165824        | 25165824
1             | 25165824        | 25165824
2             | 18874368        | 18874368
3             | 18874368        | 18874368
4             | 18874368        | 18874368
5             | 12582912        | 12582912
6             | 12582912        | 12582912
7             | 12582912        | 12582912

Where –

-1 is the total memory.
0..7 are NUMA memory nodes.

Session Memory

Memory for session management is taken from the MOT local memory.

Memory usage by all active sessions (connections) is possible using the following query –

select * from mot_session_memory_detail();

Result –

sessid                   | total_size | free_size | used_size
---------------------------------––––––-+-----------+----------+----------
1591175063.139755603855104 | 6291456    | 1800704   | 4490752

Legend –

total_size – is allocated for the session
free_size – not in use
used_size – In actual use

The following query enables a DBA to determine the state of local memory used by the current session –

select * from mot_session_memory_detail() 
 where sessid = pg_current_sessionid();

Result –