Fixes are available
APAR status
Closed as program error.
Error description
Error "Expected latch to be held" followed by a DB2 abend. The error "Expected latch to be held" is reported in the db2diag.log indicating that bufferpool services was not able to find an expected latch. The following entries may appear in the db2diag log file: 2009-01-03-10.47.55.921983-480 I181512511A437 LEVEL: Error PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, buffer pool services, sqlbReadAndReleaseBlock, probe:120 MESSAGE : ZRC=0x87020036=-2029912010=SQLB_BADHDR "Bad Page Header" DIA8547C An error occurred in a database page header. 2009-01-03-10.47.55.938946-480 E181513297A2121 LEVEL: Severe (OS) PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, SQO Latch Tracing, SQLO_SLATCH_CAS64::releaseConflictComple, probe:330 MESSAGE : ZRC=0x870F011E=-2029059810=SQLO_LATCH_ERROR_EXPECTED_HELD "expected latch to be held." CALLSTCK: [0] 0xFFFFFFFF7C86D4B8 __1cRSQdDLO_SLATCH_CAS64WreleaseConflictComplex6M_v_ + 0x6A8 [1] 0xFFFFFFFF7B181FA0 __1cXsqlbReadAndReleaseBlock6FpnLSQdDLB_FIX_CB_pnUSQdDLB_BLOCK_V ICTIM_CB_IpnLSQdDLB_pfMisc__i_ + 0xB90 [2] 0xFFFFFFFF7B17EA3C __1cQsqlbProcessRange6FpnQSQdDLB_OBJECT_DESC_IIpnLSQdDLB_pfMisc _i_ + 0x50C [3] 0xFFFFFFFF7B17EE0C __1cXsqlbServiceRangeRequest6FpnLSQdDLB_pfMisc__i_ + 0x174 [4] 0xFFFFFFFF7B17AC88 __1cbAsqlbPFPrefetcherEntryPoint6FpcI_v + 0x9F8 [5] 0xFFFFFFFF7C917A24 sqloEDUEntry + 0x3A4 [6] 0xFFFFFFFF777D266C _thr_slot_offset + 0x484 [7] 0x0000000000000000 ?unknown + 0x0 [8] 0x0000000000000000 ?unknown + 0x0 [9] 0x0000000000000000 ?unknown + 0x0 The symptoms when this issue can happen: 1. "BAD PAGE" message is not always present when the issue is encountered. 2. When block based bufferpools are used 3. When there are a lot of concurrent activities against the bufferpools
Local fix
Disable block based bufferpools: DB2 ALTER BUFFERPOOL <buff_pool_name> NUMBLOCKPAGES 0 OR The fix for IZ20119 reduces the likelihood of running into this problem. or Tune block based bufferpools.
Problem summary
Users Affected: All Problem Description: The error "Expected latch to be held" is reported in the db2diag.log indicating that bufferpool services was not able to find an expected latch. The following entries may appear in the db2diag log file: 2009-01-03-10.47.55.921983-480 I181512511A437 LEVEL: Error PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, buffer pool services, sqlbReadAndReleaseBlock, probe:120 MESSAGE : ZRC=0x87020036=-2029912010=SQLB_BADHDR "Bad Page Header" DIA8547C An error occurred in a database page header. 2009-01-03-10.47.55.938946-480 E181513297A2121 LEVEL: Severe (OS) PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, SQO Latch Tracing, SQLO_SLATCH_CAS64::releaseConflictComple, probe:330 MESSAGE : ZRC=0x870F011E=-2029059810=SQLO_LATCH_ERROR_EXPECTED_HELD "expected latch to be held." CALLSTCK: [0] 0xFFFFFFFF7C86D4B8 __1cRSQdDLO_SLATCH_CAS64WreleaseConflictComplex6M_v_ + 0x6A8 [1] 0xFFFFFFFF7B181FA0 __1cXsqlbReadAndReleaseBlock6FpnLSQdDLB_FIX_CB_pnUSQdDLB_BLOCK_V ICTIM_CB_IpnLSQdDLB_pfMisc__i_ + 0xB90 [2] 0xFFFFFFFF7B17EA3C __1cQsqlbProcessRange6FpnQSQdDLB_OBJECT_DESC_IIpnLSQdDLB_pfMisc _i_ + 0x50C [3] 0xFFFFFFFF7B17EE0C __1cXsqlbServiceRangeRequest6FpnLSQdDLB_pfMisc__i_ + 0x174 [4] 0xFFFFFFFF7B17AC88 __1cbAsqlbPFPrefetcherEntryPoint6FpcI_v + 0x9F8 [5] 0xFFFFFFFF7C917A24 sqloEDUEntry + 0x3A4 [6] 0xFFFFFFFF777D266C _thr_slot_offset + 0x484 [7] 0x0000000000000000 ?unknown + 0x0 [8] 0x0000000000000000 ?unknown + 0x0 [9] 0x0000000000000000 ?unknown + 0x0 The symptoms when this issue can happen: 1. "BAD PAGE" message is not always present when the issue is encountered. 2. When block based bufferpools are used 3. When there are a lot of concurrent activities against the bufferpools Problem Summary: The error "Expected latch to be held" is reported in the db2diag.log indicating that bufferpool services was not able to find an expected latch. The following entries may appear in the db2diag log file: 2009-01-03-10.47.55.921983-480 I181512511A437 LEVEL: Error PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, buffer pool services, sqlbReadAndReleaseBlock, probe:120 MESSAGE : ZRC=0x87020036=-2029912010=SQLB_BADHDR "Bad Page Header" DIA8547C An error occurred in a database page header. 2009-01-03-10.47.55.938946-480 E181513297A2121 LEVEL: Severe (OS) PID : 28986 TID : 47 PROC : db2sysc 0 INSTANCE: db2inst1 NODE : 000 EDUID : 47 EDUNAME: db2pfchr (SAMPLE) 0 FUNCTION: DB2 UDB, SQO Latch Tracing, SQLO_SLATCH_CAS64::releaseConflictComple, probe:330 MESSAGE : ZRC=0x870F011E=-2029059810=SQLO_LATCH_ERROR_EXPECTED_HELD "expected latch to be held." CALLSTCK: [0] 0xFFFFFFFF7C86D4B8 __1cRSQdDLO_SLATCH_CAS64WreleaseConflictComplex6M_v_ + 0x6A8 [1] 0xFFFFFFFF7B181FA0 __1cXsqlbReadAndReleaseBlock6FpnLSQdDLB_FIX_CB_pnUSQdDLB_BLOCK_V ICTIM_CB_IpnLSQdDLB_pfMisc__i_ + 0xB90 [2] 0xFFFFFFFF7B17EA3C __1cQsqlbProcessRange6FpnQSQdDLB_OBJECT_DESC_IIpnLSQdDLB_pfMisc _i_ + 0x50C [3] 0xFFFFFFFF7B17EE0C __1cXsqlbServiceRangeRequest6FpnLSQdDLB_pfMisc__i_ + 0x174 [4] 0xFFFFFFFF7B17AC88 __1cbAsqlbPFPrefetcherEntryPoint6FpcI_v + 0x9F8 [5] 0xFFFFFFFF7C917A24 sqloEDUEntry + 0x3A4 [6] 0xFFFFFFFF777D266C _thr_slot_offset + 0x484 [7] 0x0000000000000000 ?unknown + 0x0 [8] 0x0000000000000000 ?unknown + 0x0 [9] 0x0000000000000000 ?unknown + 0x0 The symptoms when this issue can happen: 1. "BAD PAGE" message is not always present when the issue is encountered. 2. When block based bufferpools are used 3. When there are a lot of concurrent activities against the bufferpools
Problem conclusion
Problem first fixed in version 9.1 Fixpak 8
Temporary fix
Disable block based bufferpools: DB2 ALTER BUFFERPOOL <buff_pool_name> NUMBLOCKPAGES 0 OR The fix for IZ20119 reduces the likelihood of running into this problem. or Tune block based bufferpools.
Comments
APAR Information
APAR number
IZ43156
Reported component name
DB2 UDB ESE SOL
Reported component ID
5765F4102
Reported release
910
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-02-03
Closed date
2009-05-05
Last modified date
2009-05-05
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
DB2 UDB ESE SOL
Fixed component ID
5765F4102
Applicable component levels
R910 PSY
UP
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Document Information
Modified date:
05 May 2009