https://bugs.openldap.org/show_bug.cgi?id=10365
--- Comment #1 from elecharny@apache.org --- Ok, there is more than just a huge number of modifications being made, and an internal queue waiting for the socket to be ready.
Actually, the client is sending a lot of modifications using an asynchronous LdapModify, and does not wait for the response before sending a new LdapModify.
Doing so, the client is sending around 1000 LdapModify per second, and I assume the server also stacks the request in memory, waiting for each single LdapModify to be completed before trying the next one, accumulating hundreds of thousand LdapModify requests, the server being able to absorb around 160 modify/s, so each second we accumulate 840 new waiting LdapModify...
It sounds to me it's a pathological usage, and I'm not sure it requires a lot of analysis.