Specifies the algorithm used during a delete in a TEXT index.
0 – 2
0 – the delete method is selected by the cost model.
1 – forces small method for deletion. Small method is useful when the number of rows being deleted is a very small percentage of the total number of rows in the table. Small delete can randomly access the index, causing cache thrashing with large data sets.
2 – forces large method for deletion. This algorithm scans the entire index searching for rows to delete. Large method is useful when the number of rows being deleted is a high percentage of the total number of rows in the table.
0
DBA permissions are not required to set this option. Can be set temporary, for an individual connection, or for the PUBLIC group. Takes effect immediately.
This option chooses the algorithm used during a delete operation in a TEXT index. When this option is not set or is set to 0, the delete method is selected by the cost model. The cost model considers the CPU-related costs as well as I/O-related costs in selecting the appropriate delete algorithm. The cost model takes into account:
Rows deleted
Index size
Width of index data type
Cardinality of index data
Available temporary cache
Machine-related I/O and CPU characteristics
Available CPUs and threads
To force the large method for deletion from a TEXT index:
SET TEMPORARY OPTION TEXT_DELETE_METHOD = 2
See “Optimizing delete operations” in Chapter 3, “Optimizing Queries and Deletions” in the Performance and Tuning Guide.
