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Hot swap cache data storage
The demander node will initialize a preloaded partition file as a new PageStore, make this storage up-to-date by applying previously saved async cache operations and then hot swap it under the checkpoint write lock.
Disadvantages:
- A long and complex index reduild procedure that requires the development of additional crash recovery guarantees.
The index rebuild procedure starts immediately when the partition file is fully received from the supplier node. If the node crashes in the middle of the rebuilding index process it will have an inconsistent index state at the further node startup. To avoid this a new index-undo WAL record must be logged within rebuilding and used on node start to remove previously added index records.
Preload entries from loaded partition file
The demander node will use a preloaded patition file as a new source of cache data entries to load.
Disadvantages:
- The approach will require a new temporary FilePageStore to be initialized. It must be created as a part of the temporary cache group or in the separate temporary data region to provide reusing machinery of iteration over the full partition file.
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