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facebook / mysql-5.6

Facebook's branch of the Oracle MySQL database. This includes MyRocks.
http://myrocks.io
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make long range scans faster for MyRocks #723

Open mdcallag opened 7 years ago

mdcallag commented 7 years ago

I will update this with data soon. Enabling file system readahead for MyRocks makes some full table scans much faster, even on fast SSD. The only way to do this today is global which will effect all sessions/queries so we need a way to limit this to long range scans.

This might be relevant for figuring out when to do it http://mysqlserverteam.com/mysql-8-0-faster-batch-record-retrieval/

mdcallag commented 6 years ago

Almost a 2X improvement from filesystem readahead on IO-bound sysbench full index scans - http://smalldatum.blogspot.com/2017/11/sysbench-io-bound-small-server-myrocks_29.html

mdcallag commented 6 years ago

My sysbench and insert benchmark results include numbers for scan - http://smalldatum.blogspot.com/2017/12/myrocks-innodb-and-tokudb-summary.html

yoshinorim commented 6 years ago

RocksDB added support for adaptive read ahead by default (https://github.com/facebook/rocksdb/commit/df23e80e5f3bc64a6802be58971066ccd35923d3). I confirmed that I/O unit size increased from 5KB to 80KB on my test table.