Remove split list nodes from buf_page_t
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
Percona Server moved to https://jira.percona.com/projects/PS |
Invalid
|
Low
|
Unassigned | ||
5.1 |
Won't Fix
|
Low
|
Unassigned | ||
5.5 |
Triaged
|
Low
|
Unassigned | ||
5.6 |
Invalid
|
Low
|
Unassigned |
Bug Description
The buffer pool mutex split patch in 5.1 and 5.5 patches struct buf_page_struct to remove
and to add
/* resplit for optimistic use */
UT_LIST_
UT_LIST_
UT_LIST_
instead. The goal of this patching is not clear. Having separate list nodes would suggest that a buffer page might be present in two or three of these list simultaneously, but that's not done (and impossible to do, and I don't see what sense would this make) in the current code. Thus, the only visible effect is, quoting Alexey -
>> On the other hand, we are looking at a non-trivial buf_page_t size
>> increase (112 bytes before the patch, 144 bytes after). Leaving all
>> cache and memory locality questions aside, that’s 64 MB of memory
>> just for list node pointers on a system with a 32 GB buffer pool.
They are being removed in the 5.6 port in progress. This bug is to remove them from 5.5 as well.
tags: | added: bp-split low-hanging-fruit xtradb |
Percona now uses JIRA for bug reports so this bug report is migrated to: https:/ /jira.percona. com/browse/ PS-2043