Hi David, Unfortunately for *ORDER BY Priority DESD, DueTime ASC* there is no technical solution in general, for how typical Tree-based index are implemented, the sorting is make in ascending order, so you cannot mix asc/desc on index-based sorting. I suspect it's true for any db implementation, but I do not have a proof for that
Thanks Luigi 2016-05-04 18:01 GMT+02:00 David López Pérez <davlope...@gmail.com>: > > Hi Luigi, > > (I am a co-worker of Hung, the original author of this post) > > Thank you very much for your answer. Creating the following index really > improved the performance of that query (without @rid in ORDER BY clause). > > CREATE INDEX Task.PriorityDueTime ON Task (Priority, DueTime) NOTUNIQUE > > We tried that solution in the past, but it doesn't work because we were > doing *ORDER BY Priority DESD, DueTime ASC*, and with that mixed ordering > direction this solution does not work. > We can also achieve our target with *ORDER BY Priority **DESD**, DueTime * > *DESC*, so your answer is valid for us. > > Thank you very much again. > David. > > > El miércoles, 4 de mayo de 2016, 11:48:09 (UTC+2), Luigi Dell'Aquila > escribió: >> >> Hi, >> >> The problem here is that the result set can be sorted using the index >> when you define ORDER BY Priority DESC, but when you add other >> conditions like ORDER BY Priority DESC, @rid ASC then the index becomes >> useless and the result set has to be sorted in memory. >> For the second case (ORDER BY Priority DESC, DueTime DESC) you can >> define a composite index on Priority and DueTime, this should speed up the >> query a lot. >> When @rid is involved in general, indexes are not helpful, because the >> rid cannot be indexed in current release >> >> Thanks >> >> Luigi >> >> -- > > --- > You received this message because you are subscribed to the Google Groups > "OrientDB" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to orient-database+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- --- You received this message because you are subscribed to the Google Groups "OrientDB" group. To unsubscribe from this group and stop receiving emails from it, send an email to orient-database+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
