SQL/MX UPDATE STATISTICS Enhancements

For each test table, the results show the number of columns on which statistics are gathered and the

actual run times, in minutes, for the pre-2.1.1 and Release 2.1.1 versions of UPDATE STATISTICS.

For the same sample size, the Release 2.1.1 version of UPDATE STATISTICS is approximately 1 to 2

percent slower than its predecessors.. However, with Release 2.1.1, you can use smaller sample

sizes and achieve better performance and accuracy.

The last column in the table compares the performance of UPDATE STATISTICS in Release 2.1.1 using

the smaller sample size for each table to the performance of pre-2.1.1 UPDATE STATISTICS using the

larger sample size. The smaller sample size yields a performance increase in the 15 to 30 percent

range. In all six of the test tables, using the smaller sample size with Release 2.1.1 provides greater

accuracy than using the larger sample size with previous versions of UPDATE STATISTICS.