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Benedict resolved CASSANDRA-6810. --------------------------------- Resolution: Duplicate > SSTable and Index Layout Improvements/Modifications > --------------------------------------------------- > > Key: CASSANDRA-6810 > URL: https://issues.apache.org/jira/browse/CASSANDRA-6810 > Project: Cassandra > Issue Type: Improvement > Components: Core > Reporter: Benedict > Labels: performance > Fix For: 3.0 > > > Right now SSTables are somewhat inefficient in their storage of composite > keys. I propose resolving this by merging (some of) the index functionality > with the storage of keys, through introducing a composite btree/trie > structure (e.g. string b-tree) to represent the key, and for this structure > to index into the cell position in the file. This structure can then serve as > both an efficient index and the key data itself. > If we then offer the option of (possibly automatically decided for you at > flush) storing this either packed into the same file directly prepending the > data, or in a separate key file (with small pages), with an uncompressed page > cache we can get good performance for wide rows by storing it separately and > relying on the page cache for CQL row index lookups, whereas storing it > inline will allow very efficient lookups of small rows where index lookups > aren't particularly helpful. This removal of extra data from the index file, > however, will allow CASSANDRA-6709 to massively scale up the efficiency of > the key cache, whilst also reducing the total disk footprint of sstables and > (most likely) offering better indexing capability in similar space -- This message was sent by Atlassian JIRA (v6.2#6252)