DC015007 SOS CONDITION errors in storage pool 255
Article ID: 26662
Updated On:
Products
Issue/Introduction
CV is issuing short on storage (SOS) messages for pool 255:
DC015007 Vnn POOL 255: SOS CONDITION 0, SZ=nnnn, T=aaaaaaaa, P=aaaaaaaa
DC015007 Vnn POOL 255: SOS CONDITION 1, SZ=nnnn, T=aaaaaaaa, P=aaaaaaaa
If PTF RO97690 is applied, many instances of the following message may also appear prior to pool 255 going SOS:
DC040107 LOCK MANAGER SECONDARY STORAGE REQUESTED
These symptoms of storage pool 255 going SOS, potentially followed by storage pool 0 also going SOS, can be caused by the allocation of lock overflow storage. If a job requires more storage for locks than has been allocated at startup, additional storage is obtained from storage pool 255. Lock overflow storage is restricted to XA storage but once pool 255 fills, it may overflow to pool 0 (depending on the release of IDMS) causing that pool to also overflow.
Excessive use of locks is usually caused by long running batch programs which do not COMMIT often enough. There is however one type of processing that can cause excessive use of locks even with COMMITs coded in the program. An ERASE with the ALL MEMBERS option can cause many records to be deleted with a single DML verb without returning control to the program. It will ERASE the target record and all related members. If the member record is also the owner of a set, its members are also deleted. This continues with the members of the members until all records in the network structure are deleted. This has the potential to do a massive number of deletes (and accumulate a large number of locks) without the program having the opportunity to control this with COMMITs. In this situation it is best to recode the program to walk the sets and ERASE each member individually, issuing COMMITs every so often.
Environment
IDMS, all supported releases.
Resolution
Use LOCKMON STATUS or DCMT D LOCK STAT to confirm if the SOS is caused by lock overflow storage.
Storage for locks is acquired at startup according to the value specified in the SYSLOCKS parameter in the SYSTEM statement of the SYSGEN.
The recommended value for SYSLOCKS is 100,000. Increase it if it is below this value.
Additional Information
See section SYSTEM Statement Parameters Info and DCMT DISPLAY LOCKS Command in IDMS TECHDOCs.
See also the following articles for additional causes of this error:
DC015007 SOS messages for a storage pool that is neither full nor marked SOS
DC015007 SOS abends or over-use of resources by OLQ
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