PV_SESSION_MEMORY_DETAIL

PV_SESSION_MEMORY_DETAIL displays statistics about thread memory usage by memory context.

The memory context TempSmallContextGroup collects information about all memory contexts whose value in the totalsize column is less than 8192 bytes in the current thread, and the number of the collected memory contexts is recorded in the usedsize column. Therefore, the totalsize and freesize columns for TempSmallContextGroup in the view display the corresponding information about all the memory contexts whose value in the totalsize column is less than 8192 bytes in the current thread, and the usedsize column displays the number of these memory contexts.

You can run the SELECT * FROM pv_session_memctx_detail (threadid,''); statement to record information about all memory contexts of a thread into the threadid_timestamp.log file in the /tmp/dumpmem directory. threadid can be obtained from the following table.

**Table 1** PV_SESSION_MEMORY_DETAIL columns
Column	Type	Description
sessid	Text	Thread start time + Thread ID + Node name (string format: timestamp.threadid.nodename)
sesstype	Text	Thread name
contextname	Text	Name of the memory context
level	Smallint	Hierarchy of the memory context
parent	Text	Name of the parent memory context
totalsize	Bigint	Total size of the memory context, in bytes
freesize	Bigint	Total size of released memory in the memory context, in bytes
usedsize	Bigint	Size of used memory in the memory context, in bytes. For TempSmallContextGroup, this parameter specifies the number of collected memory contexts.

Example

Query the usage of all MemoryContexts on the current node.

Locate the thread in which the MemoryContext is created and used based on sessid. Check whether the memory usage meets the expectation based on totalsize, freesize, and usedsize to see whether memory leakage may occur.

    
     
       
       
         SELECT * FROM pv_session_memory_detail;
                 sessid                  |        sesstype        |                  contextname                   | level |            parent            | totalsize | freesize | usedsize 
-----------------------------------------+------------------------+------------------------------------------------+-------+------------------------------+-----------+----------+----------
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | TempSmallContextGroup                          |     0 |                              |    646520 |   125184 |      149
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | TopMemoryContext                               |     0 |                              |    372672 |    19488 |   353184
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | Record information cache                       |     1 | TopMemoryContext             |     24576 |    13632 |    10944
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | Operator class cache                           |     1 | TopMemoryContext             |     24576 |    15168 |     9408
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | smgr relation table                            |     1 | TopMemoryContext             |     24576 |    11040 |    13536
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | TransactionAbortContext                        |     1 | TopMemoryContext             |     32768 |    32704 |       64
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | Portal hash                                    |     1 | TopMemoryContext             |     24576 |    16192 |     8384
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | CacheMemoryContext                             |     1 | TopMemoryContext             |   1858848 |    10640 |  1848208
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | InvalidCacheMemoryContext                      |     2 | CacheMemoryContext           |   2088960 |   828928 |  1260032
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | WAL record construction                        |     1 | TopMemoryContext             |     49792 |     6528 |    43264
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | LOCAL LOCK hash                                |     1 | TopMemoryContext             |     24576 |    15936 |     8640
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | Timezones                                      |     1 | TopMemoryContext             |     24576 |    15808 |     8768
 1760444600.140326303563096.coordinator1 | GlobalDeadLockDetector | SELF MEMORY CONTEXT                            |     1 | TopMemoryContext             |     66600 |    17824 |    48776
 1760444600.140326303562480.coordinator1 | file_recyclebin        | TempSmallContextGroup                          |     0 |                              |    642688 |   129040 |      147
 1760444600.140326303562480.coordinator1 | file_recyclebin        | TopMemoryContext                               |     0 |                              |   1437632 |    14256 |  1423376
 1760444600.140326303562480.coordinator1 | file_recyclebin        | Operator class cache                           |     1 | TopMemoryContext             |     24576 |    15168 |     9408
 1760444600.140326303562480.coordinator1 | file_recyclebin        | smgr relation table                            |     1 | TopMemoryContext             |     24576 |    11040 |    13536
 1760444600.140326303562480.coordinator1 | file_recyclebin        | TransactionAbortContext                        |     1 | TopMemoryContext             |     32768 |    32704 |       64
 1760444600.140326303562480.coordinator1 | file_recyclebin        | Portal hash                                    |     1 | TopMemoryContext             |     24576 |    16192 |     8384
 1760444600.140326303562480.coordinator1 | file_recyclebin        | CacheMemoryContext                             |     1 | TopMemoryContext             |   1858848 |    12096 |  1846752

        

      

    
   