Product Documentation

SQL Operations Guide

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SETENV TPE_MM_CACHESIZE

LEGACY Option

Specifies the size, in kilobytes, of the memory cache used for temporary tables. The default value is 1,000 Kb of memory. The internal storage system uses this cache for storing temporary tables when sorting and creating dynamic indexes during processing. Increasing TPE_MM_CACHESIZE improves performance by reducing the need to write to the on-disk swap file.

The TPE_MM_CACHESIZE setting determines how much memory the SQL engine uses for its temporary tables for each SQL client. Increasing this setting increases the amount of temporary table data the FairCom DB SQL stores in memory instead of writing this data to the disk-based swap file. But note that this memory is allocated for each SQL client, so you should consider how many clients will connect to the server at any given time and make sure total cache memory doesn't exceed available physical memory on the system.

These swap files can be found during an active connection with a filename beginning with ‘M’ followed by a string of random alphanumerics. These files can sometimes be left around after an abnormal server shutdown. They can be safely deleted once the server has been properly shut down.

Example

SETENV TPE_MM_CACHESIZE=1024

Important: The MM subsystem was replaced with a new architecture beginning with V10.3. Only enable the legacy MM subsystem on the advice of FairCom's engineering team.

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