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由 Naman Gupta 提交于
Summary: Currently for each put, a fresh memory is allocated, and a new entry is added to the memtable with a new sequence number irrespective of whether the key already exists in the memtable. This diff is an attempt to update the value inplace for existing keys. It currently handles a very simple case: 1. Key already exists in the current memtable. Does not inplace update values in immutable memtable or snapshot 2. Latest value type is a 'put' ie kTypeValue 3. New value size is less than existing value, to avoid reallocating memory TODO: For a put of an existing key, deallocate memory take by values, for other value types till a kTypeValue is found, ie. remove kTypeMerge. TODO: Update the transaction log, to allow consistent reload of the memtable. Test Plan: Added a unit test verifying the inplace update. But some other unit tests broken due to invalid sequence number checks. WIll fix them next. Reviewers: xinyaohu, sumeet, haobo, dhruba CC: leveldb Differential Revision: https://reviews.facebook.net/D12423 Automatic commit by arc
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