In addition to the problem with trx_list scan we discussed in
Friday’s post, there is another issue in
InnoDB transaction processing that notably affects MySQL
performance – for every transaction InnoDB creates a read view and allocates memory for this
structure from heap. The problem is that the heap for that
allocation is destroyed on each commit and thus the read view
memory is reallocated on the next transaction.
There are two aspects of this problem:
1) memory allocation is an costly operation and if memory …
[Read more]