The threads table provides information about threads running in the NDB kernel.

The threads table contains the following columns:

Notes

Sample output from a 2-node example cluster, including thread descriptions, is shown here:

mysql> SELECT * FROM threads;
+---------+--------+-------------+------------------------------------------------------------------+
| node_id | thr_no | thread_name | thread_description                                               |
+---------+--------+-------------+------------------------------------------------------------------+
|       5 |      0 | main        | main thread, schema and distribution handling                    |
|       5 |      1 | rep         | rep thread, asynch replication and proxy block handling          |
|       5 |      2 | ldm         | ldm thread, handling a set of data partitions                    |
|       5 |      3 | recv        | receive thread, performing receive and polling for new receives  |
|       6 |      0 | main        | main thread, schema and distribution handling                    |
|       6 |      1 | rep         | rep thread, asynch replication and proxy block handling          |
|       6 |      2 | ldm         | ldm thread, handling a set of data partitions                    |
|       6 |      3 | recv        | receive thread, performing receive and polling for new receives  |
+---------+--------+-------------+------------------------------------------------------------------+
8 rows in set (0.01 sec)

NDB 8.0.23 introduces the possibility to set either of the ThreadConfig arguments main or rep to 0 while keeping the other at 1, in which case the thread name is main_rep and its description is main and rep thread, schema, distribution, proxy block and asynch replication handling. It is also possible beginning with NDB 8.0.23 to set both main and rep to 0, in which case the name of the resulting thread is shown in this table as main_rep_recv, and its description is main, rep and recv thread, schema, distribution, proxy block and asynch replication handling and handling receive and polling for new receives.