The SET option PREFETCH_BUFFER_LIMIT defines the number of cache pages available to Sybase IQ for use in prefetching (the read ahead of database pages). This option has a default value of 0. Do not set this option unless advised to do so by Sybase Technical Support. For more information, see “PREFETCH_BUFFER_LIMIT option” in the Sybase IQ Reference Manual.
The SET option BT_PREFETCH_MAX_MISS controls the way IQ determines whether to continue prefetching pages for a given query. If queries using HG indexes run more slowly than expected, try gradually increasing the value of this option. For more information, see “BT_PREFETCH_MAX_MISS option” in the Sybase IQ Reference Manual.
