- 6.4 NDB Kernel Blocks
- 6.4.1 The BACKUP Block
- 6.4.2 The CMVMI Block
- 6.4.3 The DBACC Block
- 6.4.4 The DBDICT Block
- 6.4.5 The DBDIH Block
- 6.4.6 DBLQH Block
- 6.4.7 The DBTC Block
- 6.4.8 The DBTUP Block
- 6.4.9 DBTUX Block
- 6.4.10 The DBUTIL Block
- 6.4.11 The LGMAN Block
- 6.4.12 The NDBCNTR Block
- 6.4.13 The NDBFS Block
- 6.4.14 The PGMAN Block
- 6.4.15 The QMGR Block
- 6.4.16 The RESTORE Block
- 6.4.17 The SUMA Block
- 6.4.18 The TSMAN Block
- 6.4.19 The TRIX Block
This is the logical cluster management block, and handles node
membership in the cluster via heartbeats.
QMGR is responsible for polling the data
nodes when a data node failure occurs and determining that the
node has actually failed and should be dropped from the cluster.
This block contains the following files, found in
storage/ndb/src/kernel/blocks/qmgr:
Qmgr.hpp. Defines the Qmgr class and associated structures, including those used in detection of node failure and cluster partitioning.QmgrInit.cpp. Implements data and record initilization methods forQmgr, as well as its destructor.QmgrMain.cpp. Contains routines for monitoring of heartbeats, detection and handling of “split-brain” problems, and management of some startup phases.timer.hpp. Defines theTimerclass, used byNDBto keep strict timekeeping independent of the system clock.
This block also assists in the early phases of data node startup.
The QMGR block is implemented by the
Qmgr class, whose definition is found in the
file
storage/ndb/src/kernel/blocks/qmgr/Qmgr.hpp.
