RocksDB doesn't have midpoint insertion strategy, but has an option "ReadOptions.fill_cache = false" so that it does not insert blocks into block cache.
There are several choices for implementing this.
Adding session variable (i.e. rocksdb_not_fill_cache) and enable in mysqldump. This is probably the easiest to implement. It is hard to prevent ad-hoc queries but in practice it is good enough if disabling in mysqldump.
Adding a comment flag (i.e. SQL_NO_ROCKSDB_CACHE) and enable in mysqldump. This is harder than adding session variable because MySQL layer (sql_yacc) needs to be changed.
Making MyRocks smart enough to decide whether filling cache or not, by statistics (type=ALL and rows being large enough). This may cause issues when people intend to warm up cache.
Summary:
This diff adds a new session variable rocksdb_skip_fill_cache (default
false, and enabled at mysqldump), and set ReadOptions.fill_cache = false if turned on.
This avoids mysqldump filling block cache.
Test Plan: new test case mysqldump2
Reviewers: maykov, spetrunia, hermanlee4
Reviewed By: hermanlee4
Differential Revision: https://reviews.facebook.net/D39195
Summary:
This diff adds a new session variable rocksdb_skip_fill_cache (default
false, and enabled at mysqldump), and set ReadOptions.fill_cache = false if turned on.
This avoids mysqldump filling block cache.
Test Plan: new test case mysqldump2
Reviewers: maykov, spetrunia, hermanlee4
Reviewed By: hermanlee4
Differential Revision: https://reviews.facebook.net/D39195
RocksDB doesn't have midpoint insertion strategy, but has an option "ReadOptions.fill_cache = false" so that it does not insert blocks into block cache.
There are several choices for implementing this.