DB2 - Problem description
Problem IT27044 | Status: Closed |
DB2 MAY HANG IN ACCESSING GLFH FILE WHEN USING MULTIPLE CONCURRENT IMPORT IN DPF | |
product: | |
DB2 FOR LUW / DB2FORLUW / B10 - DB2 | |
Problem description: | |
Import is using the SYSIBMADM.DBCFG interface to get config parameter values from all partitions just in case the db config is not the same on all partitions in DPF environment , so the selecting from SYSIBMADM.DBCFG broadcast the request to all nodes to get data. When all nodes got the request, they all need to access GLFH file each will acquire latch and then lock the file. When multiple concurrent Import all query at the same time, this may cause massive contention on the same file lock, and db2 may hang there . we will see repeat invoking of statement like : SELECT SUBSTR(value, 1, 20) FROM SYSIBMADM.DBCFG WHERE name = CAST('decflt_rounding' AS VARCHAR(15)) Also we can see from db2pd -api that both last sql statement and current sql statment is same selecting from SYSIBMAMD.DBCFG AnchID StmtUID NumEnv NumVar NumRef NumExe Text 873 1087 1 1 364 364 SELECT SUBSTR(value, 1, 20) FROM SYSIBMADM.DBCFG WHERE name = CAST('decflt_rounding' AS VARCHAR(15)) 621 7502 1 1 366 366 SELECT VALUE FROM SYSIBMADM.DBCFG WHERE NAME = 'varchar2_compat' The stack will be like : _syscall6(0xfffffffcec3ebb20,0xffffffff7eaa91f0,0x2,0xffffffffff ffffff,0xfffffffcec3eb9c4,0x1002f4360) + 0x20 __pos4obj_unlink(0xfffffffcec3ebb20,0xffffffff7eaa91f0,0x2,0xfff fffffffffffff,0xfffffffcec3eb9c4,0x1002f4360) + 0x24 sem_open(0xfffffffcec3ebb20,0x0,0x0,0x1593d4,0x0,0x0) + 0x3dc __1cSOSSHIPCSemaphoreExGcreate6MkpknbCOSSIPCSemaphoreExCreatePar am__I_(0xfffffffcec3ec0d8,0xfffffffcec3ec0a8,0x0,0x4b5400,0xffff ffffffffffff,0xfffffffcec3ebb21) + 0x250 __1cVsqlnlsGetCCInfoFromCC6FL_pknPsqlnls_cc_table__(0xfffffffcec 3ecf98,0x0,0x40001,0xfffffffcec3ec218,0x1b0,0xfffffffcec3ec0d8) + 0x3a50 sqloNLCKUnlock(0xfffffffcec3ecf98,0xfffffffcec3fffff,0x4f40634,0 x3632800,0x40001,0x40000) + 0x244 __1cMSQdDLP_GLFH_CBGunlock6M_i_(0xfffffffcec3ecf70,0xffffffff665 7d870,0x4e07f4c,0x18800000,0x40000,0x3632b28) + 0x80 __1cOsqlpgCloseGLFH6FpnMSQdDLP_GLFH_CB__i_(0xfffffffcec3ecf70,0x 0,0x4e192dc,0x3632800,0xffffffff62f4ad48,0x40000) + 0xe4 __1cTsqlpBuildParmsNoDPS6FpknIsqeAgent_pkc4iIIpIII5pnNSQdDLP_LH_ PARMS__i_(0x0,0xfffffffcec3f3168,0x201752861,0x1,0x3,0xfffffffce c3effc8) + 0x694 __1cIsqlpglhu6FpknIsqeAgent_pkc4iIIpIII5pnNSQdDLP_LH_PARMS__i_(0 x0,0x201752861,0x0,0x0,0xfffffffcec3f3ec0,0x0) + 0x580 __1cIsqlfgtlp6FIpvpI1pkcpc_i_(0x2,0x0,0xfffffffcec3f3ec4,0xfffff ffcec3f3ec0,0x201752861,0xfffffffcec3f3fec) + 0x12c __1cYsqlfInitDbCfgParamForGet6Fpc00kipnLdb2CfgParam_pnKsqlf_dbcf d_pnFsqlca_ipnQsqeLocalDatabase__i_(0xfffffffcfdb0bff0,0x0,0x70, 0xffffffff60a1c0b5,0x1000,0x201752968) + 0x350 __1cMsqlfGetDbCfg6FpnQsqeLocalDatabase_pnGdb2Cfg_ipnFsqlca__i_(0 x201750080,0xfffffffcec3fc318,0x201752861,0x202899368,0x40000,0x 0) + 0x96c __1cQsqlrwGetDBConfig6FpnIsqlrr_cb_pnUsqlrwGetDBConfigArgs_ppvpl _i_(0xffffffff7516a420,0xffffffff365623f0,0xfffffffcec3fc4f8,0xf ffffffcec3fc4f0,0x0,0x0) + 0x128 __1cbEsqlrwGetWLMTableFunctionResult6FpnIsqlrr_cb_pnUsqlrw_rpc_t f_request_ppvplb_i_(0xffffffff7516a420,0xffffffff365623f0,0xffff fffcec3fc4f8,0xfffffffcec3fc4f0,0xffffffff5e882bb0,0x70) + 0x48c | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * ALL * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 11.1 Mod 4 Fixpack 5 or higher * **************************************************************** | |
Local Fix: | |
Reduce the IMPORT concurrency | |
Solution | |
Workaround | |
not known / see Local fix | |
BUG-Tracking | |
forerunner : IT25793 follow-up : | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 20.11.2018 16.01.2020 16.01.2020 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |