Page History

...

While the demander node is in the partition file transmission state it must save sequentially all cache entries corresponding to the movingMOVING partition into a new temporary WAL storage. These entries will be applied later one by one on the newly received cache partition file. All asynchronous operations will be enrolled to the end of temporary WAL storage during storage reads until it becomes fully read. The file-based FIFO approach assumes to be used by this process.

The new write-ahead-log manager for writing temporary records temporary storage is chosen to be WAL-based. The storage must support to:

• Unlimited number of walWAL-files to store temporary data records;
• Iterating over stored data records during an asynchronous writer thread inserts insert new records;
• WAL-per-partiton approach is need to be used;
• Write operations to temporary WAL storage must have higher priority over read operations;

...

Expected problems to be solved

...

• We must stop updating indexes on demander when the data is ready to be transferred from the supplier node. All async cache updates on demander must not cause the index update;
• The previous partition metadata page and all stored meta information must be destroyed in memory and restored from the new partition file;

Working diagram

Rebuild indexes

The node is ready to become partition owner when partition data is rebalanced and cache indexes are ready. For the message-based cluster rebalancing approach indexes are rebuilding simultaneously with cache data loading. For the file-based rebalancing approach, the index rebuild procedure must be run before the partition state is set to the OWNING state. 

...