Hash access paths
(deprecated)
Db2 can use hash access paths to
directly access a single row in a table and avoid scanning the table or index.
Hash-organized
table spaces are deprecated and likely to be unsupported in the future.
FL 504 Hash-organized tables are deprecated. Beginning in Db2 12, packages that are bound with APPLCOMPAT(V12R1M504) or higher cannot create hash-organized tables or alter existing tables to use hash-organization. Existing hash-organized tables remain supported, but they are likely to be unsupported in the future.
Db2 can generate a hash access path from the equal predicate of an SQL statement that fetches only a single row of a table. This access method is faster and more efficient than scanning the table or the index.
Hash access can reduce the query access time and the CPU load for queries that require access to a single row. However, tables that are enabled for hash access might require as much as twice the amount of disk space as tables that are not organized for hash access.