On 5/11/2022 3:48 AM, Soisik Froger wrote:
Are this performance issues an expected side-effect of switching to dynlist - as the memberOf attributes are now dynamically calculated while the memberOf overlay used to writes these attributes - or
I am also having ongoing sporadic issues with memberOf performance using the new dynlist overlay. Initially, randomly a server would get into a state where any query requesting the memberOf attribute would take in excess of 30 seconds, whereas normally it would only take a fraction of a second. The symptoms were the same, free memory, no swapping, but insanely high read IO load.
I cranked up the memory, which not did resolve the issue, but did help, it doesn't happen nearly as often. But still, every now and again, a server demonstrates a high read IO rate and severely degraded memberOf query performance. At this point, I just have a monitoring check that alerts on slow query performance and high read I/O and go restart them when it happens, as the additional memory made the issue go from a couple of times a week to every month or three.
I did notice now that when the issue occurs the box with the slow queries does have less memory available then when it is working normally, but still a good gigabyte of free memory not being used.
Even when the systems don't completely blow up, there are occasional slower than normal queries. Typically the test query I am doing literally takes fractions of a second:
May 21 19:47:22 ldap-01 slapd[1223]: conn=849157 op=1 SEARCH RESULT tag=101 err=0 qtime=0.000015 etime=0.198042 nentries=1 text=
Every now and again for no discernible reason it might take 5 to 10 seconds.
