NUMTHREADS view

The DVSYS.NUMTHREADS view provides a summary of the total number of Java virtual machine (JVM) threads.

For more information on JVM threads, see Thread.

Table 1. DVSYS.NUMTHREADS
Column	Type	Description
NODE_NAME	VARCHAR(80)	Name of the node where the query ran.
GRP	VARCHAR(80)	The thread group, which represents a set of threads.
NAME	VARCHAR(128)	The name of the thread.
NUMTHREADS	BIGINT	The number of threads for NODE_NAME, GRP, and NAME. Note: Threads with similar thread names are grouped together if there isn't a `NAME IS NULL` predicate.

The NUMTHREADS view has two variations:

Variation 1

The first variation calls the query without a predicate on the NAME column. The output displays the number of threads (NUMTHREADS) based on the node name (NODE_NAME), thread group (GRP), and name. The thread names are displayed by truncating the dash (-) or by underscoring (_) the numeric identifier.

Example thread names: Thread, NetworkServerThread, Timer

Example call and output:

SELECT * FROM DVSYS.NUMTHREADS

NODE_NAME                GRP                      NAME                       NUMTHREADS
-----------------------------------------------------------------------------------------------------
AdminNode           derby.daemons           NetworkServerThread                 1
AdminNode           derby.daemons           derby.NetworkServerStarter          1
AdminNode           derby.daemons           derby.rawStoreDaemon                1
AdminNode           derby.daemons           DRDAConnThread                      2
AdminNode           InnocuousThreadGroup    Common-Cleaner                      1
AdminNode           main                    DB Connections checker              1
AdminNode           main                    DiscoveryServerTCP                  1
AdminNode           main                    GaianNode Watchdog                  1
AdminNode           main                    Thread                              1
fmp_1               system                  JIT Diagnostic Compilation Thread   1
fmp_1               system                  JIT-SamplerThread                   1
fmp_1               system                  GC Worker                           3
fmp_1               system                  JIT Compilation Thread              7
cdb2udvdvendpoint0  derby.daemons           GaianDataSourceExecutor             1
cdb2udvdvendpoint0  derby.daemons           NetworkServerThread                 1

Variation 2

The second variation calls the query with NAME IS NULL. The output displays the total number of threads (NUMTHREADS) of the same group, based on the node name (NODE_NAME) and thread group (GRP). There are no thread names.

Example call and output:

SELECT * FROM DVSYS.NUMTHREADS WHERE NAME IS NULL

NODE_NAME    GRP                   NAME        NUMTHREADS 

------------------------------------------------------------------------

AdminNode InnocuousThreadGroup      -              1

AdminNode derby.daemons             -              6

AdminNode main                      -              16

AdminNode system                    -              29