The details on this issue are here:
https://github.com/facebook/mysql-5.6/issues/369
This test is very simple. I loaded the SSB (star schema
benchmark) data for scale factor 20 (12GB raw data), added
indexes, and tried to count the rows in the table.
After loading data and creating indexes, the .rocksdb data
directory is 17GB in size.
A full table scan "count(*)" query takes less than four minutes,
sometimes reading over 1M rows per second, but when scanning the
index to accomplish the same count, the database can only scan
around 2000 rows per second. The four minute query would take an
estimated 1000 minutes, a 250x difference.
I have eliminated the type of CRC32 function (SSE vs non-SSE) by
forcing the hardware SSE function by patching the code.
There seem to be problems with any queries …
The details on this issue are here:
https://github.com/facebook/mysql-5.6/issues/369
This test is very simple. I loaded the SSB (star schema
benchmark) data for scale factor 20 (12GB raw data), added
indexes, and tried to count the rows in the table.
After loading data and creating indexes, the .rocksdb data
directory is 17GB in size.
A full table scan "count(*)" query takes less than four minutes,
sometimes reading over 1M rows per second, but when scanning the
index to accomplish the same count, the database can only scan
around 2000 rows per second. The four minute query would take an
estimated 1000 minutes, a 250x difference.
I have eliminated the type of CRC32 function (SSE vs non-SSE) by
forcing the hardware SSE function by patching the code.
There seem to be problems with any queries …