MICRORIM_FULLOPT is a system variable that controls the number of tables that are optomized in a query.
Normally, five tables are optimized in a query. For queries using more than five tables, the MICRORIM_FULLOPT variable can be used to specify the number of tables to optimize.
In general, the R:BASE optimizer makes the correct choice for selecting the fastest method to execute a query, which is that five tables are optimized. Option 2 of MICRORIM_EXPLAIN will force optimization of all tables in a query. MICRORIM_FULLOPT specifies the number of tables to optimize. For queries using over five tables, use MICRORIM_FULLOPT to specify the number of tables to optimize. The more tables that are optimized, the longer the optimization process takes. While you can decrease the data retrieval time by specifying MICRORIM_FULLOPT, you can also increase the optimization time which might counteract the decrease in data retrieval time. As with all optimization techniques, you need to test them with your data.
For queries (SELECTs) using many tables, MICRORIM_FULLOPT specifies the number of tables to be fully optimized. The number MICRORIM_FULLOPT is set to is the number of tables that are fully optimized. Tables above the number specified are only partially optimized. The tables that are optimized are determined by their order in the FROM clause of the query. This variable overrides the optimization part of MICRORIM_EXPLAIN. If MICRORIM_FULLOPT exists, then the 2-bit option of MICRORIM_EPLAIN is ignored.
The command below fully optimizes the first eight tables in a query. If there are more than eight tables in a query, the remaining tables are partially optimized.
SET VAR MICRORIM_FULLOPT = 8
