DB2 - Problem description
| Problem IT09084 | Status: Closed | 
| NO TIMEOUT MECHANISM IN GLM LOCK SIZE MANAGEMENT THREAD CAUSED HANG ISSUE | |
| product: | |
| DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
| Problem description: | |
| This problem only happens when CFMT feature is 
enabled(DB2_DATABASE_CF_MEMORY=AUTO). 
 
When db2periodicc is doing GLM lock resize,  it would 
periodically query CF for the GLM size to see if it has 
allocated to the target size, due to the lack of timeout 
mechanism, it might hang when the new size can not be achieved 
at CF side. In one known case, db2periodicc hangs and keeps 
holding latch SQLO_LT_SQLE_GSS_HEADER,  as a result the other 
applications get blocked waiting for this latch. 
 
A sample call stack of  EDU db2periodicc: 
 
0x00002AAAAACDAC6D recvmsg + 0x002d 
        (/lib64/libpthread.so.0) 
0x00002AAAB795EE8F address: 0x00002AAAB795EE8F ; dladdress: 
0x00002AAAB7905000 ; offset in lib: 0x0000000000059E8F ; 
        (/db2home/db2sdin1/sqllib/lib64/libca_api.so) 
0x00002AAAB795FB07 mp_send_cmd + 0x01b7 
        (/db2home/db2sdin1/sqllib/lib64/libca_api.so) 
0x00002AAAB795289E PsLockAllocate + 0x033e 
        (/db2home/db2sdin1/sqllib/lib64/libca_api.so) 
0x00002AAAAE1A000D 
_ZN19SAL_AllocateLockCmd29managementLockAllocateOrAlterEP9MgmntP 
ortm + 0x028d 
        (/db2home/db2sdin1/sqllib/lib64/libdb2e.so.1) 
0x00002AAAB03F1B48 
_ZN26SAL_MANAGEMENT_PORT_HANDLE20SAL_ManagementResizeEPKcmbjtttP 
jS2_P34SQLE_CA_MGMNT_EXTENDED_RESIZE_INFO + 0x09a8 
        (/db2home/db2sdin1/sqllib/lib64/libdb2e.so.1) 
0x00002AAAB03B69AE 
_ZN20SAL_CA_STRUCT_HANDLE30SAL_CADoStructureResizeCommandER22SAL 
_MANAGEMENT_HANDLESmP29SQLF_CA_STRUCT_RESIZE_ELEMENTjPjS4_ + 
0x015e 
        (/db2home/db2sdin1/sqllib/lib64/libdb2e.so.1) 
0x00002AAAB03B39CA 
_ZN20SAL_CA_STRUCT_HANDLE23sqlfResizeStructureInCAEP29SQLF_CA_ST 
RUCT_RESIZE_ELEMENTPb + 0x022a 
        (/db2home/db2sdin1/sqllib/lib64/libdb2e.so.1) 
0x00002AAAAE26AD0A sqlfCAStructureResizeBackgroundTask + 0x09ea 
        (/db2home/db2sdin1/sqllib/lib64/libdb2e.so.1) | |
| Problem Summary: | |
| **************************************************************** * USERS AFFECTED: * * N/A * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 V10.5 FIXPACK 7. * **************************************************************** | |
| Local Fix: | |
| Disable CFMT feature by setting DB2_DATABASE_CF_MEMORY to a value other than AUTO. | |
| Solution | |
| The problem is firstly fixed on V10.5 FIXPACK 7. | |
| Workaround | |
| not known / see Local fix | |
| Timestamps | |
| Date - problem reported : Date - problem closed : Date - last modified : | 25.05.2015 20.01.2016 20.01.2016 | 
| Problem solved at the following versions (IBM BugInfos) | |
| Problem solved according to the fixlist(s) of the following version(s) | |
| 10.5.0.7 |  | 







 
