Hi, So here is the last set of benchmark results, this time from ext4 on a small SATA-based RAID (3 x 7.2k). As before, I'm only attaching PDFs with the simple charts, full results are available in the git repository [1]. Overall the numbers are rather boring, with almost no difference between the two setups.
That being said, I'm not opposed to introducing the GUC. I'm not going to pretend my tests represents all possible HW configs and workloads, and I have no trouble believing that it may be quite beneficial in some cases. The one comment about the code is that we usually use the actual default value in the config sample. But the patch does this: +#wal_recycle = off # do not recycle WAL files while the GUC is defined like this: { {"wal_recycle", PGC_SUSET, WAL_SETTINGS, gettext_noop("WAL recycling enabled."), NULL }, &wal_recycle, true, NULL, NULL, NULL }, So the default is actually "on" which makes the commented-out config sample rather confusing. regards -- Tomas Vondra http://www.2ndQuadrant.com PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
ext4-sata.pdf
Description: Adobe PDF document