On Apr 24, 2017, at 3:04 PM, jocelyn fournier <jocelyn.fournier@gmail.com> wrote:

You should search read_rnd_buff_size, it's used in sql/records.cc to compute the size of the cache_records in the READ_RECORD struct.

But, the original link implied use with mrr, however, this page:

https://mariadb.com/kb/en/mariadb/multi-range-read-optimization/

Says:

"MariaDB uses mrr_buffer_size as a limit of MRR buffer size for range access, while MySQL uses read_rnd_buffer_size.”

So, I guess it is still used, but, not for mrr.

Steve