Chapter 4 NDB Kernel Blocks

Table of Contents

4.1 The BACKUP Block

4.2 The CMVMI Block

4.3 The DBACC Block

4.4 The DBDICT Block

4.5 The DBDIH Block

4.6 The DBINFO Block

4.7 The DBLQH Block

4.8 The DBSPJ Block

4.9 The DBTC Block

4.10 The DBTUP Block

4.11 The DBTUX Block

4.12 The DBUTIL Block

4.13 The LGMAN Block

4.14 The NDBCNTR Block

4.15 The NDBFS Block

4.16 The PGMAN Block

4.17 The QMGR Block

4.18 The RESTORE Block

4.19 The SUMA Block

4.20 The THRMAN Block

4.21 The TRPMAN Block

4.22 The TSMAN Block

4.23 The TRIX Block

This chapter provides information about the major software modules making up the NDB kernel. The files containing the implementations of these blocks can be found in several directories under storage/ndb/src/kernel/blocks/ in the NDB Cluster source tree.

As described elsewhere, the NDB kernel makes use of a number of different threads to perform various tasks. Kernel blocks are associated with these threads as shown in the following table:

Table 4.1 NDB kernel blocks and NDB kernel threads

Thread (ThreadConfig Name)	Kernel Blocks
Main (main)	CMVMI (primary), DBINFO, DBDICT, DBDIH, NDBCNTR, QMGR, DBUTIL
LDM (ldm)	DBTUP, DBACC, DBLQH (primary), DBTUX, BACKUP, TSMAN, LGMAN, PGMAN, RESTORE
TC (tc)	DBTC (primary), TRIX
Replication (rep)	SUMA (primary), DBSPJ
Receiver (recv)	CMVMI
Sender (send)	CMVMI
I/O (io)	NDBFS
Query (query)	DBQTUP, DBQACC, DBQLQH, DBQTUX, QBACKUP QRESTORE
Recovery (recover)	DBQTUP, DBQACC, DBQLQH, DBQTUX, QBACKUP QRESTORE

NDB 8.0.22 and later provides for the following combinations:

• main and rep threads, as threads of type main_rep

• main, rep, and recv threads, as threads of type main_rep_recv

The query and recover thread types were added in NDB 8.0.23.

You can obtain more information about these threads from the documentation for the ThreadConfig data node configuration parameter.