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comparison src/sqlcache.sml @ 2300:57f6473b1469

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More work on heuristics.
author Ziv Scully <ziv@mit.edu>
date Thu, 19 Nov 2015 18:13:01 -0500
parents 47d5c94aeeb8
children 8d772fbf59c1
comparison
equal deleted inserted replaced
2299:47d5c94aeeb8 2300:57f6473b1469
91 91
92 val cacheRef = ref LruCache.cache 92 val cacheRef = ref LruCache.cache
93 fun setCache c = cacheRef := c 93 fun setCache c = cacheRef := c
94 fun getCache () = !cacheRef 94 fun getCache () = !cacheRef
95 95
96 datatype heuristic = Always | Never | NoPureAll | NoPureOne | NoCombo 96 datatype heuristic = SmartEq (* | SmartSub *) | Always | Never | NoPureAll | NoPureOne | NoCombo
97 97
98 val heuristicRef = ref Always 98 val heuristicRef = ref Always
99 fun setHeuristic h = heuristicRef := (case h of 99 fun setHeuristic h = heuristicRef := (case h of
100 "always" => Always 100 "smarteq" => SmartEq
101 (* | "smartsub" => SmartSub *)
102 | "always" => Always
101 | "never" => Never 103 | "never" => Never
102 | "nopureall" => NoPureAll 104 | "nopureall" => NoPureAll
103 | "nopureone" => NoPureOne 105 | "nopureone" => NoPureOne
104 | "nocombo" => NoCombo 106 | "nocombo" => NoCombo
105 | _ => raise Fail "Sqlcache: setHeuristic") 107 | _ => raise Fail "Sqlcache: setHeuristic")
611 IM.empty 613 IM.empty
612 (varsOfQuery q))] 614 (varsOfQuery q))]
613 615
614 val union = op@ 616 val union = op@
615 617
618 fun addToSqlArgsMap ((q, subst), acc) =
619 IM.foldl (fn (arg, acc) => AM.insert (acc, arg, ())) acc subst
620
616 fun sqlArgsMap (qs : t) = 621 fun sqlArgsMap (qs : t) =
617 let 622 let
618 val args = 623 val args =
619 List.foldl (fn ((q, subst), acc) => 624 List.foldl addToSqlArgsMap AM.empty qs
620 IM.foldl (fn (arg, acc) => AM.insert (acc, arg, ())) acc subst)
621 AM.empty
622 qs
623 val countRef = ref (~1) 625 val countRef = ref (~1)
624 fun count () = (countRef := !countRef + 1; !countRef) 626 fun count () = (countRef := !countRef + 1; !countRef)
625 in 627 in
626 (* Maps each arg to a different consecutive integer, starting from 0. *) 628 (* Maps each arg to a different consecutive integer, starting from 0. *)
627 AM.map count args 629 AM.map count args
645 val invalPaths = List.foldl PS.union PS.empty (map freePaths args) 647 val invalPaths = List.foldl PS.union PS.empty (map freePaths args)
646 (* TODO: make sure these variables are okay to remove from the argument list. *) 648 (* TODO: make sure these variables are okay to remove from the argument list. *)
647 val pureArgs = PS.difference (paths, invalPaths) 649 val pureArgs = PS.difference (paths, invalPaths)
648 val shouldCache = 650 val shouldCache =
649 case getHeuristic () of 651 case getHeuristic () of
650 Always => true 652 SmartEq =>
651 | Never => (case qs of [_] => true | _ => false) 653 (case (qs, PS.numItems pureArgs) of
654 ((q::qs), 0) =>
655 let
656 val m = addToSqlArgsMap (q, AM.empty)
657 val ms = map (fn q => addToSqlArgsMap (q, AM.empty)) qs
658 fun test (m, acc) =
659 acc
660 <\obind\>
661 (fn m' =>
662 let
663 val mm = AM.unionWith #1 (m, m')
664 in
665 AM.numItems m = AM.numItems mm
666 <\oguard\>
667 (fn _ => SOME mm)
668 end)
669 in
670 case List.foldl test (SOME m) ms of
671 NONE => false
672 | SOME _ => true
673 end
674 | _ => false)
675 | Always => true
676 | Never => (case qs of [_] => PS.numItems pureArgs = 0 | _ => false)
652 | NoPureAll => (case qs of [] => false | _ => true) 677 | NoPureAll => (case qs of [] => false | _ => true)
653 | NoPureOne => (case qs of [] => false | _ => PS.numItems pureArgs = 0) 678 | NoPureOne => (case qs of [] => false | _ => PS.numItems pureArgs = 0)
654 | NoCombo => PS.numItems pureArgs = 0 orelse AM.numItems argsMap = 0 679 | NoCombo => PS.numItems pureArgs = 0 orelse AM.numItems argsMap = 0
655 in 680 in
656 (* Put arguments we might invalidate by first. *) 681 (* Put arguments we might invalidate by first. *)