My Oracle Support Banner

Poor IMAP Response Time, Many imapd Threads, High Memory Usage (Doc ID 1332578.1)

Last updated on JANUARY 03, 2023

Applies to:

Oracle Communications Messaging Server - Version 5.2.0 and later
Information in this document applies to any platform.


On some backend message store systems, the imapd processes begin consuming more memory than usual around peak load time and response time degrades.  Restarting imapd clears the problem until the next peak load time.

The increased memory usage is actually a side effect.  The primary symptoms would be degraded response time and increased number of threads waiting in the mmap() syscall.  See more details in the Cause section below.


Customer recently upgraded from Messaging Server 5.2 to 7.x and did not maintain similar configuration/tuning parameters.

Note that this issue could also be caused by steady usage growth, which might not be noticed as a "change".


To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!

In this Document
 Other disk-related tuning: store.dbtmpdir and local.lockdir
 Results after tuning

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.