Support query for output record derivation trace. #725

yjiayu · 2020-08-05T21:45:41Z

Add maps to store all debug event entries and extract output record and its input record
and store these information.
Add helper function to get predecessor operatorId for input record from syntax tree
Add tree-like 'DebuggerRecordNode' structure to store all possible derivation results
for a given output record with operator id.

haroldlim · 2020-08-06T07:29:41Z

debugger/Main.hs

+    d''' <- case confOutputInput of
+         "" -> return d''
+         x  ->  return $ progMirrorInputRelations d'' x
+    when confDumpFlat $


I don't think we need to add this option to dump the transformed program in the debugger program. If we want to dump it, we can always use the ddlog binary to do it.

haroldlim · 2020-08-06T07:35:50Z

debugger/Main.hs

+parseProgram Config{..} = do
+    fdata <- readFile confDatalogFile
+    (d, _, _) <- parseDatalogProgram (takeDirectory confDatalogFile:confLibDirs) True fdata confDatalogFile
+    d'' <- case confOutputInternal of


This means that we have to ensure that we pass the same options when we compiled the ddlog program and here.
Instead of loading the original program here (and ensuring the same options are passed), I wonder if we can just load the dumped transformed source here? I haven't thought about it deeply yet, so not sure if it's possible to generate DatalogProgram from an ast file?

haroldlim · 2020-08-06T07:37:53Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

@@ -0,0 +1,179 @@
+{-
+Copyright (c) 2018-2020 VMware, Inc.


Not sure what the convention is for new files, but usually the year here should be the year it was added (i.e., just 2020)

@haroldlim , yep

haroldlim · 2020-08-06T07:51:33Z

debugger/Main.hs

+                s = queryAll events (dbgRecordMap recordMap)
+            putStr $ show s
+
+queryAll :: [Event] -> DebuggerRecordMap -> String


So, currently the debugger tool will just print/query all derivations of all output records?

Not required for this change, but I wonder if we can make it more interactive (i.e., list out the output records, and then we can specify which output record we want to trace the derivation).

Yeah, for now the debugger tool's function is
queryDerivations :: DebuggerRecord -> DebuggerRecordMap -> DebuggerRecordNode
It takes one output record and debuggerRecordMap (got built when parsing log events) and return the root node of the derivations since the derivation result is a tree like structure.
According to Leonid, we are planning to design a UI that will take the debugger output and then display it in a better way, probably is a next step work.

ryzhyk

Thanks, @yjiayu! The overall structure looks good, I think we're on the right track. I have a bunch of comments on specific data structures and algorithms. @yjiayu, we can go through them in detail when you're available.

ryzhyk · 2020-08-09T17:29:54Z

debugger/Main.hs

+import Language.DifferentialDatalog.Validate
+import Language.DifferentialDatalog.Debug
+
+data TOption = Help


I don't think we need to copy all flags from the DDlog executable. LibDir and Help seem like the only relevant ones.

ryzhyk · 2020-08-09T17:34:28Z

src/Language/DifferentialDatalog/Config.hs

@@ -51,6 +51,7 @@ data Config = Config { confDatalogFile   :: FilePath
                     , confDumpDebug     :: Bool
                     , confDumpOpt       :: Bool
                     , confReValidate    :: Bool
+                     , confDebugDumpFile :: FilePath


Debugger should have its own Config type, which should include this field.

ryzhyk · 2020-08-09T17:36:02Z

src/Language/DifferentialDatalog/Debug.hs

@@ -182,12 +183,17 @@ insertRHSInspectDebugHooks d rlIdx rule =

 debugUpdateRHSRules :: DatalogProgram -> Int -> Rule -> [RuleRHS]
 debugUpdateRHSRules d rlIdx rule =
+  let rhs = debugUpdateRHSRulesWithoutHooks d rlIdx rule


We discussed this offline, but just to make sure we're on the same page, with #729 we should not need to perform any kind of preprocessing in the debugger, right?

ryzhyk · 2020-08-09T17:36:47Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

@@ -0,0 +1,179 @@
+{-
+Copyright (c) 2018-2020 VMware, Inc.


@haroldlim , yep

ryzhyk · 2020-08-09T17:40:37Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+type DebuggerRecordMap = M.Map DebuggerRecord [Derivation]
+type DebuggerRecordWeightMap = M.Map DebuggerRecord Int
+
+data OperatorInput = InputOp OperatorId


A comment here would be great.

ryzhyk · 2020-08-09T19:06:36Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+            in case traceRecords of
+                Nothing ->  let updatedDbgRecordMap = M.insert outputRecord [derivation] dbgRecordMap
+                            in DebuggerMaps { dbgRecordMap = updatedDbgRecordMap, dbgRecordWeightMap = updatedDbgRecordWeightMap}
+                Just derivations -> let updatedDbgRecordMap = M.insert outputRecord (derivations ++ [derivation]) dbgRecordMap


This will introduce duplicate derivations, and because we do not track individual derivation weights, we won't be able to eliminate mutually canceling derivations.

ryzhyk · 2020-08-09T19:08:15Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+                Just derivations -> let updatedDbgRecordMap = M.insert outputRecord (derivations ++ [derivation]) dbgRecordMap
+                                    in DebuggerMaps { dbgRecordMap = updatedDbgRecordMap, dbgRecordWeightMap = updatedDbgRecordWeightMap}
+
+constructRecordMap :: [Event] -> DebuggerMaps -> DatalogProgram -> DebuggerMaps


This seems nearly identical to handleDebugEvents.

ryzhyk · 2020-08-09T19:19:32Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+-- Get the operator if for input records in a debug entry
+getPredecessorOpId :: OperatorId -> DatalogProgram-> [OperatorInput]
+getPredecessorOpId OperatorId{..} DatalogProgram{..} =
+    let Rule{..} = progRules !! ruleIdx


This will crash if ruleIdx is out of range. We should not trust input data. One way to deal with this is to run functions that can fail inside MonadError. See, e.g., Validate.hs for examples of this.

ryzhyk · 2020-08-09T19:56:47Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+            if rhsIdx == 0
+            then [InputRel (atomRelation rhsAtom)]
+            else let prevRuleRhs = ruleRHS !! (rhsIdx - 1)
+                 in case prevRuleRhs of


I think the case analysis here should not be whether prevRuleRhs is a literal or not, but rather whether rhsIdx - 1 == 0.

ryzhyk · 2020-08-09T19:58:43Z

src/Language/DifferentialDatalog/Debugger/DebugState.hs

+                        _ -> [InputOp OperatorId {ruleIdx = ruleIdx, rhsIdx = (rhsIdx - 1), headIdx = headIdx}, InputRel (atomRelation rhsAtom)]
+        RHSCondition{..} -> let prevRhsIdx = getPredecessorRHSRuleIdxForCondition rhsIdx ruleRHS
+                        in [InputOp OperatorId {ruleIdx = ruleIdx, rhsIdx = prevRhsIdx, headIdx = headIdx}]
+        _ -> [InputOp OperatorId {ruleIdx = ruleIdx, rhsIdx = (rhsIdx - 1), headIdx = headIdx}]


Here we want to consider two cases, based on whether rhsIdx - 1 == 0. If it is then we want InputRel, otherwise InputOp

1. Add maps to store all debug event entries and extract output record and its input record and store these information. 2. Add helper function to get predecessor operatorId for input record from syntax tree 3. Add tree-like 'DebuggerRecordNode' structure to store all possible derivation results for a given output record with operator id.

yjiayu force-pushed the master-derivation branch from 3f97622 to 3d7ec5c Compare August 5, 2020 23:00

haroldlim reviewed Aug 6, 2020

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ryzhyk suggested changes Aug 9, 2020

View reviewed changes

yjiayu force-pushed the master-derivation branch from 3d7ec5c to f9c78d7 Compare September 2, 2020 22:51

yjiayu force-pushed the master-derivation branch from f9c78d7 to 0fc2d4f Compare September 14, 2020 17:06

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Support query for output record derivation trace. #725

Support query for output record derivation trace. #725

yjiayu commented Aug 5, 2020

haroldlim Aug 6, 2020

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Support query for output record derivation trace. #725

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Support query for output record derivation trace. #725

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