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Yes, if the optimizer chooses a reverse index plan then it will distinguish this in the plan. Example: create table foo( i int primary key); insert into foo( i ) select row_num from sa_rowgenerator( 1, 999999 ); commit; select explanation( 'select i from foo where i between 333333 and 333444 order by i asc' ); --> result is foo<foo(IO)> select explanation( 'select i from foo where i between 333333 and 333444 order by i desc' ); --> result is foo<foo(R,IO)> Note that the 'R' in the second plan means "reverse". 1
FWIW: I see that 'R' is missing from the [list of plan abbreviations][1] in the docs - I will ask to have it added. [1] http://dcx.sybase.com/index.html#1201/en/dbusage/abbreviations-plan-queryopt.html
(23 May '11, 10:54)
Mark Culp
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question asked: 23 May '11, 02:49
question was seen: 1,996 times
last updated: 23 May '11, 10:54
You mean when you have an index on colA ASC and the query would sort by colA DESC?
(No, I don't know the answer...)
yes, I know the "index scan" strategy in the plans of the optimizer, but will a "reverse index scan" be explicitly named?