Query explain

static - In static mode, explain doesn't run the query, but instead prints only the static structure of the query plan.

details - In details mode, explain runs the query, and includes dynamic aspects of the query plan. These may include the number of intermediate bindings flowing through the operators, the ratio of incoming bindings to outgoing bindings, and the total time taken by each operator. Additional details, such as the actual openCypher query string and the estimated range count for the pattern underlying a join operator, are also shown.

DFEApply – Executes the function specified by functor in the arguments section, on the value stored in the specified variable

DFEAlgoWriteProperty – Explain operator for the property-writing portion of mutate algorithm invocations.

DFEBFSAlgo – Explain operator for invocations of the Breadth First Search algorithm, which searches for nodes from a starting vertex (or starting vertices, also called multi-source BFS) in a graph in breadth-first order.

DFEBindRelation – Binds together variables with the specified names.

DFEChunkLocalSubQuery – This is a non-blocking operation that acts as a wrapper around subqueries being performed.

DFEClosenessCentralityAlgo – Explain operator for invocations of the Closeness Centrality algorithm, which computes a metric that can be used as a positive measure of how close a given node is to all other nodes or how central it is in the graph.

DFECommonNeighborsAlgo – Explain operator for invocations of the Common Neighbors algorithm, which counts the number of common neighbors of two input nodes.

DFECreateConstant – Extends the given input relation with new columns containing constant values.

DFEDegreeAlgo – Explain operator for invocations of the Degree algorithm, which calculates the number of edges that are incident to a vertex.

DFEDistinctColumn – Returns the distinct subset of the input values based on the variable specified.

DFEDistinctRelation – Returns the distinct subset of the input solutions based on the variable specified.

DFEDrain – Appears at the end of a subquery to act as a termination step for that subquery. The number of solutions is recorded as Units In. Units Out is always zero.

DFEForwardValue – Copies all input chunks directly as output chunks to be passed to its downstream operator.

DFEGroupByHashIndex – This is a blocking operation that organizes the rows of a relation according to a set of variables, outputting a single group identifier column that is one-to-one with the rows of the input relation. Groups here are defined by the join variables used to build the hash index (See DFEHashIndexBuild for where this hash index might be built.)

DFEHashIndexBuild – Builds a hash index over a set of variables as a side-effect. This hash index is typically reused in later operations. (See DFEHashIndexJoin for where this hash index might be used.)

DFEHashIndexJoin – Performs a join over the incoming solutions against a previously built hash index. (See DFEHashIndexBuild for where this hash index might be built.)

DFEJaccardSimilarityAlgo – Explain operator for invocations of the Jaccard similarity algorithm, which measures the similarity between two sets of nodes.

DFEJoinExists – Takes a left and right hand input relation, and retains values from the left relation that have a corresponding value in the right relation as defined by the given join variables.

DFELabelPropagationAlgo – Explain operator for invocations of the Label Propagation algorithm, which is used for community detection.

DFELoopSubQuery – This is a non-blocking operation that acts as a wrapper for a subquery, allowing it to be run repeatedly for use in loops.

DFEMergeChunks – This is a blocking operation that combines chunks from its upstream operator into a single chunk of solutions to pass to its downstream operator (inverse of DFESplitChunks).

DFEMinus – Takes a left and right hand input relation, and retains values from the left relation that do not have a corresponding value in the right relation as defined by the given join variables. If there is no overlap in join variables across both relations, then this operator simply returns the left hand input relation as is.

DFENotExists – Takes a left and right hand input relation, and retains values from the left relation that do not have a corresponding value in the right relation as defined by the given join variables. If there is no overlap in join variables, then this operator will return an empty relation.

DFEOptionalJoin – Performs the optional join A OPTIONAL B ≡ (A JOIN B) UNION (A MINUS_NE B). This is a blocking operation.

DFEOverlapSimilarityAlgo – Explain operator for invocations of the Overlap Similarity algorithm, which measures the overlap between the neighbors of two nodes.

DFEPageRankAlgo – Explain operator for invocations of the Page Rank algorithm, which calculates a score for a given node based on the number, quality, and importance of the edges pointing to that node.

DFEPipelineJoin – Joins the input against the tuple pattern defined by the pattern argument.

DFEPipelineRangeCount – Counts the number of solutions matching a given pattern, and returns a single solution containing the count value.

DFEPipelineScan – Scans the database for the given pattern argument, with or without a given filter on column(s).

DFEProject – Takes multiple input columns and projects only the desired columns.

DFEReduce – Performs the specified aggregation function on specified variables.

DFERelationalJoin – Joins the input of the previous operator based on the specified pattern keys using a merge join. This is a blocking operation.

DFERouteChunks – Takes input chunks from its singular incoming edge and routes those chunks along its multiple outgoing edges.

DFESCCAlgo – Explain operator for invocations of the Strongly Connected Components algorithm, which calculates the maximally connected subgraphs of a directed graph where every node is reachable from every other node.

DFESelectRows – This operator selectively takes rows from its left input relation solutions to forward to its downstream operator. The rows selected based on the row identifiers supplied in the operator’s right input relation.

DFESerialize – Serializes a query’s final results into a JSON string serialization, mapping each input solution to the appropriate variable name. For node and edge results, these results are serialized into a map of entity properties and metadata.

DFESort – Takes an input relation and produces a sorted relation based on the provided sort key.

DFESplitByGroup – Splits each single input chunk from one incoming edge into smaller output chunks corresponding to row groups identified by row ids from the corresponding input chunk from the other incoming edge.

DFESplitChunks – Splits each single input chunk into smaller output chunks (inverse of DFEMergeChunks).

DFESSSPAlgo – Explain operator for invocations of the single source shortest path (SSSP) algorithms (Delta-stepping and Bellman-ford).

DFEStreamingHashIndexBuild – Streaming version of DFEHashIndexBuild.

DFEStreamingGroupByHashIndex – Streaming version of DFEGroupByHashIndex.

DFESubquery – This operator appears at the beginning of all plans and encapsulates the portions of the plan that are run on the DFE engine, which is the entire plan for openCypher.

DFESymmetricHashJoin – Joins the input of the previous operator based on the specified pattern keys using a hash join. This is a non-blocking operation.

DFESync – This operator is a synchronization operator supporting non-blocking plans. It takes solutions from two incoming edges and forwards these solutions to the appropriate downstream edges. For synchronization purposes, the inputs along one of these edges may be buffered internally.

DFETee – This is a branching operator that sends the same set of solutions to multiple operators.

DFETermResolution – Performs a localize or globalize operation on its inputs, resulting in columns of either localized or globalized identifiers respectively.

DFETopKSSSPAlgo – Explain operator for invocations of the TopK hop-limited single source (weighted) shortest path algorithm algorithm, which finds the single-source weighted shortest paths from a source node to its neighbors out to the distance specified by maxDepth.

DFETotalNeighborsAlgo – Explain operator for invocations of the Total Neighbors algorithm, which counts the total number of unique neighbors of two input vertices.

DFEUnfold – Unfolds lists of values from an input column into the output column as individual elements.

DFEUnion – Takes two or more input relations and produces a union of those relations using the desired output schema.

DFEVSSAlgo – Explain operator for invocations of the Vector similarity search algorithms, which find similar vectors based on the distance to each other.

DFEWCCAlgo – Explain operator for invocations of the Weakly Connected Components algorithm, which finds the weakly-connected components in a directed graph.

SolutionInjection – Appears before everything else in the explain output, with a value of one in the Units Out column. However, it serves a no-op, and doesn't actually inject any solutions into the DFE engine.

TermResolution – Appears at the end of plans and translates of objects from the Neptune engine into openCypher objects.

ID – The numeric ID of this operator in the plan.

Out #1 (and Out #2) – The ID(s) of operator(s) that are downstream from this operator. There can be at most two downstream operators.

Name – The name of this operator.

Arguments – Any relevant details for the operator. This includes things like input schema, output schema, pattern (for PipelineScan and PipelineJoin), and so on.

Mode – A label describing fundamental operator behavior. This column is mostly blank (-). One exception is TermResolution, where mode can be id2value_opencypher, indicating a resolution from ID to openCypher value.

Units In – The number of solutions passed as input to this operator. Operators without upstream operators, such as DFEPipelineScan, SolutionInjections, and a DFESubquery with no static value injected, would have zero value.

Units Out – The number of solutions produced as output of this operator. DFEDrain is a special case, where the number of solutions being drained is recorded in Units In and Units Out is always zero.

Ratio – The ratio of Units Out to Units In.

Time (ms) – The CPU time consumed by this operator, in milliseconds.