Hash-Based Update Statistics

Adaptive Server versions 15.7 ESD #2 and later allow you to gather hash-based statistics on minor index attributes and unindexed columns instead of using sort-based statistics, significantly reducing elapsed time and resource usage. Using hash-based statistics improves performance by reducing the number of required scans, and avoiding disk-based sorting.

Hash-based statistic allow greater flexibility than sort-based statistics:

Running hash-based statistics should require less time, increasing the amount you can accomplish during a maintenance window.
Because hash-based statistics require less procedure cache, you may be able to run update statistics on a data-only-locked table outside a maintenance window, since the Adaptive Server tempdb buffer cache (which typically uses the default data cache) is typically much larger than the procedure cache, reducing the impact of update statistics.
Hash-based statistics do not generally require large tempdb disk allocations. If you previously increased the size of tempdb to accommodate large sorts from update statistics, you may be able to redeploy this space.
update [index | all] statistics with hashing may run faster than update [index | all] statistics with sampling. However, an exception may be update statistics table_name(col_name).
update statistics table_name (col_name1), (col_name2) . . . with hashing allows you to collect statistics on several columns with a single scan instead of several scans.