Matching Accelerators (prefilters)

A Matching Accelerator speeds matching by quickly filtering out many table records from consideration before performing a full match calculation. Thus they are generally referred to as prefilters.

GIP, SORT, and PSI are the three prefilters that provide a large boost in search time performance.

It is strongly recommended that for any large table one of these prefilters be used. Large being a somewhat vague term, being dependent on many different factors such as number of fields, size of fields, type of queries, and performance constraints, but can be roughly construed as 100,000 records or more.

Each has certain advantages: the GIP prefilter is far more flexible and easier to use, SORT takes less memory, and can give a greater speed boost, especially on very large tables. PSI is similar to SORT, but can be more accurate in situations where SORT might not perform well. Generally, the SORT and PSI prefilters are designed for use in record matching where complete records are to be matched on a field by field basis. The SORT filter is not intended for situations where you are doing general queries that might have far less information in the query than contained in the complete record. The PSI prefilter might work well where a limited number of query types are in use. Both SORT and PSI have slightly slower record operations than GIP, so they might be inappropriate when real-time updates on large tables are required. SORT and PSI do not index variable attributes, and therefore, might not be suitable for use with tables containing variable attributes. The GIP prefilter works well for almost any kind of query and is completely transparent in use. It also performs well for record updates on any size table, but query performance on very large tables is significantly lower than the SORT and PSI prefilters. GIP uses more memory than SORT, and PSI uses more memory than GIP.

The default prefilter can be selected via the command line argument. See TIBCO Patterns Installation for details on command line arguments. If no prefilter is specified on the command line, the default is the GIP prefilter. This default prefilter applies only when a table is initially created. The default prefilter for queries is the prefilter used by the table being queried.