2. Fallback to using sql_select_limit system variable value if an explicit limit is not supplied.
3. Remove checks that did not allow (2^64 - 1) as a valid limit value.
pDictionaryScan won't work for BLOB/TEXT since it requires searching the
data file and rebuilding the token from matches. The tokens can't be
rebuild correctly due the bits in the token used for block counts. This
patch forces the use of pDictionaryStep instead for WHERE conditions.
In addition this patch adds support for TEXT/BLOB in various parts of
the job step processing. This fixes things like error 202 during an
UPDATE with a join condition on TEXT/BLOB columns.
During subquery processing it is possible to have an empty Having
clause. When this happens various tree elements are deleted but the
pointers to those tree elements are not set to NULL. So later on in
processing ExeMgr can crash.
