Hi Otto, On Fri, Jan 3, 2025 at 6:19 AM Otto Kekäläinen <otto@kekalainen.net> wrote:
It think it should be fairly clear to users if the value is innodb-log-file-mmap=false or innodb-log-file-mmap=none.
Users are already familiar with innodb-use-native-aio=false on all platforms that do not support it. I still feel strongly that having system variables that appear and disappear without external reasons is confusing to users, and this innodb-log-file-mmap is now the first system variable that has that behaviour.
Sure, I can help test pmem support on various platforms. But it will never be 100% on all platforms, so this variable visibility needs to be addressed separately.
OK. What would be the procedure to get a particular branch or commit tested on Debian Salsa CI?
Also, just to confirm, you recent work on pmem features means that pmem is still intended to be in MariaDB and the removal in https://github.com/MariaDB/server/commit/8e663f5e9041e8e0998c792bf8d0c297a8b... has been reverted?
Like that commit message says, the PMEM support was only removed from the 10.6 branch, where it made practically no performance difference. MDEV-14425 (originally in the 10.8 short-term-support release) introduced a more scalable log file format that is designed for PMEM. When I tested it on a PMEM device, I think that I observed a 15% improvement in throughput in a write heavy benchmark. While both Intel and Micron have discontinued their NVDIMM product lines, I think that the technology makes sense and hope that some options will remain. One option might be https://www.rambus.com/blogs/compute-express-link/; the blog post is a year old.
I was about to follow suite in Debian in https://salsa.debian.org/mariadb-team/mariadb-server/-/merge_requests/86 but I guess I should not anymore?
A dependency on libpmem was removed from all MariaDB Server versions, so anything related to that should also be removed from any Debian downstream packaging. InnoDB only ever needed pmem_persist() from that library, to control the flushing of some cache lines. Marko -- Marko Mäkelä, Lead Developer InnoDB MariaDB plc