NDB Cluster Internals  /  NDB Cluster Start Phases  /  START_MEREQ Handling

5.22 START_MEREQ Handling

The first step in handling START_MEREQ is to ensure that no local checkpoint is currently taking place; otherwise, it is necessary to wait until it is completed. The next step is to copy all distribution information from the master DBDIH to the starting DBDIH. After this, all metadata is synchronized in DBDICT (see Section 5.21, “System Restart Handling in Phase 4”).

After blocking local checkpoints, and then synchronizing distribution information and metadata information, global checkpoints are blocked.

The next step is to integrate the starting node in the global checkpoint protocol, local checkpoint protocol, and all other distributed protocols. As part of this the node status is also updated.

After completing this step the global checkpoint protocol is permitted to start again, the START_MECONF signal is sent to indicate to the starting node that the next phase may proceed.