75 ways to demystify DB2 #80: Techtip : IDB2 JCC Exception -4499 : No buffer space available (maximum connections reached?)
ChunGao 270006J5PY Comments (2) Visits (11053)
Users may receive the following JCC error on Windows platform:
This error can be caused by a few reasons, below are the causes and fixes:
Cause 1. User may have encountered the windows socket leak bug.
Cause 2. Physical limitation, user may not have sufficient system resources.
Cause 3. Windows configuration, user may need to increase the ephemeral (short-lived) TCP ports numbers on Windows.
Cause 4. Application opens too many physical connections to the database and ended up reaching the max connection limit on db2. This can be verified by one of the following methods :
a. checking "netstat -an" output by checking the number of established connections, you may see a large number of established connections and output similar to the following:
b. checking "db2 get snapshot for dbm" output, in this output you need to look for the following variables:
These are the indicators that the application users use is opening too many connections and reaching the max connection limitation.
Checking all causes listed above will help diagnose the exact problem.
Following are the fixes corresponding to the causes above :
Fix 1. User needs to apply Microsoft hotfix from http
Fix 2. Check user's system and expand system resources required, for example, memory.
Fix 4. We cannot fix this, the fix is with the application. User will have to modify their application so that it does not open that many connections to DB2, or, to reuse the connections.