Inserts and Queries

Well-tuned Sybase IQ insert operations exhibit certain characteristics. You can observe these characteristics from the Windows Task Manager and the Windows Performance tool.

I/O Operations

  • Insert operations are generally CPU-bound. All CPUs within the system should be running at close to 100%, with 95% or higher of the CPU being executed in user mode. You can see this easily by clicking on the Performance tab of the Windows Task Manager with the View-Show Kernel Times option set.

  • Physical memory should not be overallocated and in particular, the virtual address space for the Sybase IQ process should be less than the physical memory (RAM) for the machine.

  • Hard page faults (I/O to the volume containing pagefile.sys) should be low and ideally close to 0 (zero).

  • I/O operations to the IQ Store should be steady and within the I/O capacity of the disk subsystem.

Load Performance

Sybase IQ uses the Windows CreateFile option (for both creating and opening a file) that specifies a file is to be read for sequential access. This option is used on the files specified in the LOAD TABLE command. As a result, load performance is improved through read ahead and reduced NTFS Cache memory utilization.

Load performance can be further improved by setting the size of the main Sybase IQ buffer cache considerably smaller than the calculated recommended values. You can set the main Sybase IQ buffer cache as much as 50% smaller than the calculated recommended values.

Tuning for Queries

Reduce the size of the main buffer cache to improve query performance.

Related concepts
Main and Temp Buffer Caches
NTFS Cache