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
Name	Type	Description
sessid	text	Thread start time+thread ID (string: timestamp.threadid)
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 order by totalsize desc;
           sessid           |        sesstype         |                 contextname                 | level |            parent            | totalsize | freesize | usedsize
----------------------------+-------------------------+---------------------------------------------+-------+------------------------------+-----------+----------+----------
 0.139975915622720          | postmaster              | gs_signal                                   |     1 | TopMemoryContext             |  17209904 |  8081136 |  9128768
 1667462258.139973631031040 | postgres                | SRF multi-call context                      |     5 | FunctionScan_139973631031040 |   1725504 |     3168 |  1722336
 1667461280.139973666686720 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   284456 |  1188088
 1667450443.139973877479168 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   356088 |  1116456
 1667462258.139973631031040 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   128216 |  1344328
 1667461250.139973915236096 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   226352 |  1246192
 1667450439.139974010144512 | WLMarbiter              | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   386736 |  1085808
 1667450439.139974151726848 | WDRSnapshot             | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   159720 |  1312824
 1667450439.139974026925824 | WLMmonitor              | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   297976 |  1174568
 1667451036.139973746386688 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   208064 |  1264480
 1667461250.139973950891776 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   270016 |  1202528
 1667450439.139974076212992 | WLMCalSpaceInfo         | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   393952 |  1078592
 1667450439.139974092994304 | WLMCollectWorker        | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |    94848 |  1377696
 1667461254.139973971343104 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   338544 |  1134000
 1667461280.139973822945024 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   284456 |  1188088
 1667450439.139974202070784 | JobScheduler            | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   216728 |  1255816
 1667450454.139973860697856 | postgres                | CacheMemoryContext                          |     1 | TopMemoryContext             |   1472544 |   388384 |  1084160
 0.139975915622720          | postmaster              | Postmaster                                  |     1 | TopMemoryContext             |   1004288 |    88792 |   915496
 1667450439.139974218852096 | AutoVacLauncher         | CacheMemoryContext                          |     1 | TopMemoryContext             |    948256 |   183488 |   764768
 1667461250.139973915236096 | postgres                | TempSmallContextGroup                       |     0 |                              |    584448 |   148032 |      119
 1667462258.139973631031040 | postgres                | TempSmallContextGroup                       |     0 |                              |    579712 |   162128 |      123

        

      

    
   