With the Network Services Server option “Maximize Throughput for Network Applications” enabled, use of the NTFS and its associated cache can improve the performance of Sybase IQ for both inserts and queries. This is largely due to the NTFS being able to store significantly more data than the Sybase IQ buffer cache, with the same amount of physical memory, and the performance of the Intel Pentium to decompress Sybase IQ pages. As a result, when you use Sybase IQ on Windows platforms, you should reduce the size of the Sybase IQ buffer caches from their normal recommended settings.
The Sybase IQ main and temp buffer caches store Sybase IQ data (pages) in uncompressed form. As a result, a Sybase IQ buffer cache of 100MB can store 100MB worth of data. Conversely, the NTFS cache manages Sybase IQ data in its compressed form. Therefore, if the compression ratio were 2:1, 100MB of NTFS cache is potentially storing 200MB of Sybase IQ data. As a result, the NTFS cache is likely to sustain a higher cache hit rate which can lead to a reduction in I/O. The savings in I/O outweigh the computational overhead needed to decompress data as it moves from the NTFS cache to the Sybase IQ buffer caches.
