Add rocksdb_rows_read|inserted|updated|deleted

[hermanlee]

Issue by yoshinorim
Friday May 15, 2015 at 21:49 GMT
Originally opened as MySQLOnRocksDB#65

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We can get these from table statistics but will still be very useful if exposing as status variables. Calculating and getting these stats need to be fast enough.

[hermanlee]

Performing the row_counters need to be efficient. Using atomic counters across multiple threads (especially rows_read) can cause too much contention. Look at innodb's srv_stats_t structure on an example of how ib_counters_t were implemented.

[santoshbanda]

https://reviews.facebook.net/D49719