Sets the maximum number of rows that the IQ optimizer will consider for a hash algorithm.
Integer up to 250000000
Can be set temporary, per user, or for the PUBLIC group. DBA authority is not required to set the option. This option takes effect immediately.
2500000
When generating a query plan, the IQ optimizer may have several algorithms (hash, sort, indexed) to choose from when processing a particular part of a query. These choices often depend on estimates of the number of rows to process or generate from that part of the query. This option sets an upper boundary for how many estimated rows it will consider for a hash algorithm.
For example, if there is a join between two tables, and the estimated number of rows entering the join from both tables exceeds this option value, the optimizer will not consider a hash join. On systems with more than 50 MB per user of temporary buffer cache space, you may want to consider a higher value for this option.
