RTS,DD Cache


RTS,DD Cache

Please help me knowing a bit detail about the role of RTS and DD Cache in Parsing Engine?

What are they and what they do?

Re: RTS,DD Cache

The dictionary cache is a buffer in parsing engine memory that stores the
most recently used dictionary information. These entries, which also contain
statistical information used by the, are used to convert database object
names to their numeric IDs.

The statement, or request, cache stores successfully parsed SQL requests so
they can be reused, thereby eliminating the need for reparsing the same
request parcel. The cache is a PE buffer that stores the steps generated
during the parsing of a DML statement
The statement cache is checked at the start of the parsing process, before
the Syntaxer step, but after the Request parcel has been checked for format
errors. If the system finds a matching cache request, the Parser bypasses
the Syntaxer, Resolver, Optimizer, and Generator steps,
performs a security check (if required), and proceeds to the Apply stage.

More details you can find in Teradata manuals easily