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SQL Anywhere® Server - Database Administration  > Connection Parameters and Network Protocol Options  > Connection parameters

PrefetchBuffer connection parameter [PBUF]


Sets the maximum amount of memory for buffering rows, in bytes.

Usage

Anywhere

Values

Integer [ k | m ] between the default value and 8 MB

Default

65536 (all platforms except Windows CE)

16384 (Windows CE)

Remarks

The PrefetchBuffer (PBUF) connection parameter controls the memory allocated on the client to store prefetched rows. The default value is in bytes, but you can use k or m to specify units of kilobytes or megabytes, respectively. In some circumstances, increasing the number of rows prefetched from the database server by the client can improve query performance. You can increase the number of rows prefetched using the PrefetchRows (PROWS) and PrefetchBuffer (PBUF) connection parameters.

Increasing the PrefetchBuffer (PBUF) connection parameter also increases the amount of memory used to buffer GET DATA requests. This may improve performance for some applications that process many GET DATA (SQLGetData) requests.

For compatibility with previous versions, if a value less than 16384 is specified, it is interpreted as kilobytes. Using kilobytes without the k suffix in the PrefetchBuffer connection parameter is deprecated, and will not be supported in future versions of the software. See PrefetchRows connection parameter [PROWS].

See also
Examples

The following connection string fragment could be used to determine if the PrefetchBuffer memory limit is reducing the number of rows prefetched.

...PrefetchRows=100;LogFile=c:\client.txt

The following string could be used to increase the memory limit to 256 KB:

...PrefetchRows=100;PrefetchBuffer=256k

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