SAP Knowledge Base Article - Preview

2522495 - SAP IQ Add dbfile when using filesystem devices could take too long to complete

Symptom


Sometimes adding a new file to a dbspace could take longer than normal. For e.g in one scenario adding a 4TB file to filesystem device took only 20 secs, whereas adding another file did not complete even after 30mins.

Executing pstacks on the IQ Process will show the following functions:
===== Thread Number  140628592043776  (IQ connID: 0000799996) =====

pc: 0x7fe55d845d42 pcstkwalk(stk_trace*, int, db_log*, hos_fd*)+0x32
pc: 0x7fe55d8463b1 ucstkgentrace(int, int)+0x121
pc: 0x315640f7e0
pc: 0x315640f1a3
pc: 0x7fe55d5be3fd hos_pi_pwrite(hos_fd, void const*, unsigned int, long)+0xd
pc: 0x7fe55d5bf27c hos_pi_alloc_disk(hos_fd, long, int)+0x19c
pc: 0x7fe55d83d178 hos_svbio::PreAllocate(unsigned long long)+0xae
pc: 0x7fe55da5cd1d s_dbmvbio::CreateDiskSegment2(s_dbspace_info const&)+0x18d
pc: 0x7fe55df3a6e6 s_iqstore::CreateDBFile2(s_dbspace_info const&, int)+0x26
pc: 0x7fe55e47e9ad db_CreateDiskSegment::Execute()+0x121d
pc: 0x7fe55e318a62 st_command::DoCmdThroughResourceGate()+0x82
pc: 0x7fe55e4a3c76 db_iqphysddl::CreateDBSpaceCall2(a_statement const*, UIConnection*, UIDBSpace*)+0x26
pc: 0x7fe55d0d6b8d UIQPhysDDL_CreateDBSpaceCall2+0x1d
pc: 0x7fe55e3716c6 st_SAIQInterfaceInfo::callFunction()+0x26
pc: 0x7fe55e3dcfae st_SAIQInterface::RunIQFunc(st_SAIQInterfaceInfo*)+0x1ac
pc: 0x7fe55e37203a st_SAIQInterface::Execute(int, void*, unsigned int (*)+0x20a
pc: 0x7fe55d86b5eb saint_iqthresholdphysddl::AlterDBSpace(a_statement const*, IConnection*, IDBSpace*, unsigned int*)+0x2cb
pc: 0x7fec4ddf7086 dbi_alter_dbspace(Connection*, a_statement*)+0x1236 .iqmsg for slow execution is as follows:
I. 08/01 20:44:26. 0000799996 AlterDBSpace 16387 dbauser
I. 08/01 20:44:26. 0000799996 AlterDBSpace ADDFILE
I. 08/01 20:44:26. 0000799996 CreateDiskSegment
I. 08/01 20:44:26. 0000799996 Checked out license for 100 IQ_VLDBMGMT
I. 08/01 20:44:26. 0000799996 [20715]: Warning: SYSAM:IQ Main Store Size is 100% full with 0 bytes of free space left.
I. 08/01 20:44:26. 0000799996 [20715]: Warning: SYSAM:Increasing Main Data Store size by 1 bytes will require additional IQ_VLDBMGMT licenses.
I. 08/01 20:44:26. 0000799996 /IQ_USER/user118
I. 08/01 20:44:26. 0000799996 140628592043776 Info: posix_fallocate fd=148 sample time 0.090000 sec.
I. 08/01 20:44:26. 0000799996 140628592043776 Info: posix_fallocate fd=148 second sample time 0.010000 sec.
I. 08/01 20:44:26. 0000799996 140628592043776 Info: posix_fallocate fd=148 sample time 0.010000 sec. 
.iqmsg for fast execution is as follows:
I. 08/01 22:04:59. 0000000016 AlterDBSpace 16387 dbauser
I. 08/01 22:04:59. 0000000016 AlterDBSpace ADDFILE
I. 08/01 22:04:59. 0000000016 CreateDiskSegment
I. 08/01 22:04:59. 0000000016 Checked out license for 100 IQ_VLDBMGMT
I. 08/01 22:04:59. 0000000016 [20715]: Warning: SYSAM:IQ Main Store Size is 100% full with 0 bytes of free space left.
I. 08/01 22:04:59. 0000000016 [20715]: Warning: SYSAM:Increasing Main Data Store size by 1 bytes will require additional IQ_VLDBMGMT licenses.
I. 08/01 22:04:59. 0000000016 /IQ_USER/user118
I. 08/01 22:04:59. 0000000016 139899963422464 Info: posix_fallocate fd=148 sample time 0.000000 sec.
I. 08/01 22:04:59. 0000000016 139899963422464 Info: posix_fallocate fd=148 second sample time 0.000000 sec.
I. 08/01 22:04:59. 0000000016 139899963422464 Info: posix_fallocate fd=148 sample time 0.000000 sec.
I. 08/01 22:04:59. 0000000016 139899963422464 Info: using posix_fallocate fd=148.  Sampling threshold was 0.010000 sec.
...
I. 08/01 22:05:00. 0000000254 Disconnect:  SA connHandle: 1000000241  SA connID: 6  IQ connID: 0000000254  User: dbo

Read more...

Environment

  • SAP IQ 16.1
  • SAP IQ 16.0
  • Unix using filesystem devices

Product

SAP IQ 16.0 ; SAP IQ 16.1

Keywords

 Sybase , Hang, CR800571 , 800571, pstack , KBA , BC-SYB-IQ , Sybase IQ , How To

About this page

This is a preview of a SAP Knowledge Base Article. Click more to access the full version on SAP ONE Support launchpad (Login required).

Search for additional results

Visit SAP Support Portal's SAP Notes and KBA Search.