sql: add json encoding/decoding support for stmt/txn stats.

pkg/BUILD.bazel

@@ -279,6 +279,7 @@ ALL_TESTS = [
     "//pkg/sql/span:span_test",
     "//pkg/sql/sqlliveness/slinstance:slinstance_test",
     "//pkg/sql/sqlliveness/slstorage:slstorage_test",
+    "//pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil:sqlstatsutil_test",
     "//pkg/sql/stats:stats_test",
     "//pkg/sql/stmtdiagnostics:stmtdiagnostics_test",
     "//pkg/sql/tests:tests_test",

pkg/sql/BUILD.bazel

@@ -351,6 +351,7 @@ go_library(
         "//pkg/sql/sqlfsm",
         "//pkg/sql/sqlliveness",
         "//pkg/sql/sqlstats",
+        "//pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil",
         "//pkg/sql/sqlstats/sslocal",
         "//pkg/sql/sqltelemetry",
         "//pkg/sql/sqlutil",

pkg/sql/crdb_internal.go

@@ -56,6 +56,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/sql/sessiondata"
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlliveness"
 	"github.com/cockroachdb/cockroach/pkg/sql/sqlstats"
+	"github.com/cockroachdb/cockroach/pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil"
 	"github.com/cockroachdb/cockroach/pkg/sql/types"
 	"github.com/cockroachdb/cockroach/pkg/util/duration"
 	"github.com/cockroachdb/cockroach/pkg/util/errorutil"
@@ -851,28 +852,6 @@ func getSQLStats(p *planner, virtualTableName string) (sqlstats.Storage, error)
 	return p.extendedEvalCtx.statsStorage, nil
 }
 
-// ExplainTreePlanNodeToJSON builds a formatted JSON object from the explain tree nodes.
-func ExplainTreePlanNodeToJSON(node *roachpb.ExplainTreePlanNode) json.JSON {
-
-	// Create a new json.ObjectBuilder with key-value pairs for the node's name (1),
-	// node's attributes (len(node.Attrs)), and the node's children (1).
-	nodePlan := json.NewObjectBuilder(len(node.Attrs) + 2 /* numAddsHint */)
-	nodeChildren := json.NewArrayBuilder(len(node.Children))
-
-	nodePlan.Add("Name", json.FromString(node.Name))
-
-	for _, attr := range node.Attrs {
-		nodePlan.Add(strings.Title(attr.Key), json.FromString(attr.Value))
-	}
-
-	for _, childNode := range node.Children {
-		nodeChildren.Add(ExplainTreePlanNodeToJSON(childNode))
-	}
-
-	nodePlan.Add("Children", nodeChildren.Build())
-	return nodePlan.Build()
-}
-
 var crdbInternalStmtStatsTable = virtualSchemaTable{
 	comment: `statement statistics (in-memory, not durable; local node only). ` +
 		`This table is wiped periodically (by default, at least every two hours)`,
@@ -956,7 +935,7 @@ CREATE TABLE crdb_internal.node_statement_statistics (
 				flags = "!" + flags
 			}
 
-			samplePlan := ExplainTreePlanNodeToJSON(&stats.Stats.SensitiveInfo.MostRecentPlanDescription)
+			samplePlan := sqlstatsutil.ExplainTreePlanNodeToJSON(&stats.Stats.SensitiveInfo.MostRecentPlanDescription)
 
 			execNodeIDs := tree.NewDArray(types.Int)
 			for _, nodeID := range stats.Stats.Nodes {

pkg/sql/crdb_internal_test.go

@@ -495,130 +495,6 @@ UPDATE system.namespace SET id = 12345 WHERE id = 53;
 	require.False(t, rows.Next())
 }
 
-// TestExplainTreePlanNodeToJSON tests whether the ExplainTreePlanNode function
-// correctly builds a JSON object from an ExplainTreePlanNode.
-func TestExplainTreePlanNodeToJSON(t *testing.T) {
-	defer leaktest.AfterTest(t)()
-
-	testDataArr := []struct {
-		explainTree roachpb.ExplainTreePlanNode
-		expected    string
-	}{
-		// Test data using a node with multiple inner children.
-		{
-			roachpb.ExplainTreePlanNode{
-				Name: "root",
-				Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-					{
-						Key:   "rootKey",
-						Value: "rootValue",
-					},
-				},
-				Children: []*roachpb.ExplainTreePlanNode{
-					{
-						Name: "child",
-						Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-							{
-								Key:   "childKey",
-								Value: "childValue",
-							},
-						},
-						Children: []*roachpb.ExplainTreePlanNode{
-							{
-								Name: "innerChild",
-								Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-									{
-										Key:   "innerChildKey",
-										Value: "innerChildValue",
-									},
-								},
-							},
-						},
-					},
-				},
-			},
-			`{"Children": [{"ChildKey": "childValue", "Children": [{"Children": [], "InnerChildKey": "innerChildValue", "Name": "innerChild"}], "Name": "child"}], "Name": "root", "RootKey": "rootValue"}`,
-		},
-		// Test using a node with multiple attributes.
-		{
-			roachpb.ExplainTreePlanNode{
-				Name: "root",
-				Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-					{
-						Key:   "rootFirstKey",
-						Value: "rootFirstValue",
-					},
-					{
-						Key:   "rootSecondKey",
-						Value: "rootSecondValue",
-					},
-				},
-				Children: []*roachpb.ExplainTreePlanNode{
-					{
-						Name: "child",
-						Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-							{
-								Key:   "childKey",
-								Value: "childValue",
-							},
-						},
-					},
-				},
-			},
-			`{"Children": [{"ChildKey": "childValue", "Children": [], "Name": "child"}], "Name": "root", "RootFirstKey": "rootFirstValue", "RootSecondKey": "rootSecondValue"}`,
-		},
-		// Test using a node with multiple children and multiple inner children.
-		{
-			roachpb.ExplainTreePlanNode{
-				Name: "root",
-				Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-					{
-						Key:   "rootKey",
-						Value: "rootValue",
-					},
-				},
-				Children: []*roachpb.ExplainTreePlanNode{
-					{
-						Name: "firstChild",
-						Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-							{
-								Key:   "firstChildKey",
-								Value: "firstChildValue",
-							},
-						},
-						Children: []*roachpb.ExplainTreePlanNode{
-							{
-								Name: "innerChild",
-								Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-									{
-										Key:   "innerChildKey",
-										Value: "innerChildValue",
-									},
-								},
-							},
-						},
-					},
-					{
-						Name: "secondChild",
-						Attrs: []*roachpb.ExplainTreePlanNode_Attr{
-							{
-								Key:   "secondChildKey",
-								Value: "secondChildValue",
-							},
-						},
-					},
-				},
-			},
-			`{"Children": [{"Children": [{"Children": [], "InnerChildKey": "innerChildValue", "Name": "innerChild"}], "FirstChildKey": "firstChildValue", "Name": "firstChild"}, {"Children": [], "Name": "secondChild", "SecondChildKey": "secondChildValue"}], "Name": "root", "RootKey": "rootValue"}`,
-		},
-	}
-
-	for _, testData := range testDataArr {
-		explainTreeJSON := sql.ExplainTreePlanNodeToJSON(&testData.explainTree)
-		require.Equal(t, testData.expected, explainTreeJSON.String())
-	}
-}
-
 func TestDistSQLFlowsVirtualTables(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)

pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil/BUILD.bazel

@@ -0,0 +1,32 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "sqlstatsutil",
+    srcs = [
+        "json_decoding.go",
+        "json_encoding.go",
+        "json_impl.go",
+    ],
+    importpath = "github.com/cockroachdb/cockroach/pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/roachpb:with-mocks",
+        "//pkg/util/encoding",
+        "//pkg/util/json",
+        "@com_github_cockroachdb_apd_v2//:apd",
+        "@com_github_cockroachdb_errors//:errors",
+    ],
+)
+
+go_test(
+    name = "sqlstatsutil_test",
+    srcs = ["json_encoding_test.go"],
+    embed = [":sqlstatsutil"],
+    deps = [
+        "//pkg/roachpb:with-mocks",
+        "//pkg/util/json",
+        "//pkg/util/leaktest",
+        "//pkg/util/log",
+        "@com_github_stretchr_testify//require",
+    ],
+)

pkg/sql/sqlstats/persistedsqlstats/sqlstatsutil/json_decoding.go

@@ -0,0 +1,50 @@
+// Copyright 2021 The Cockroach Authors.
+//
+// Use of this software is governed by the Business Source License
+// included in the file licenses/BSL.txt.
+//
+// As of the Change Date specified in that file, in accordance with
+// the Business Source License, use of this software will be governed
+// by the Apache License, Version 2.0, included in the file
+// licenses/APL.txt.
+
+package sqlstatsutil
+
+import (
+	"github.com/cockroachdb/cockroach/pkg/roachpb"
+	"github.com/cockroachdb/cockroach/pkg/util/json"
+)
+
+// DecodeTxnStatsMetadataJSON decodes the 'metadata' field of the JSON
+// representation of transaction statistics into
+// roachpb.CollectedTransactionStatistics.
+func DecodeTxnStatsMetadataJSON(
+	metadata json.JSON, result *roachpb.CollectedTransactionStatistics,
+) error {
+	return jsonFields{
+		{"stmtFingerprintIDs", (*stmtFingerprintIDArray)(&result.StatementFingerprintIDs)},
+	}.decodeJSON(metadata)
+}
+
+// DecodeTxnStatsStatisticsJSON decodes the 'statistics' section of the
+// transaction statistics JSON payload into roachpb.TransactionStatistics
+// protobuf.
+func DecodeTxnStatsStatisticsJSON(jsonVal json.JSON, result *roachpb.TransactionStatistics) error {
+	return (*txnStats)(result).decodeJSON(jsonVal)
+}
+
+// DecodeStmtStatsMetadataJSON decodes the 'metadata' field of the JSON
+// representation of the statement statistics into
+// roachpb.CollectedStatementStatistics.
+func DecodeStmtStatsMetadataJSON(
+	metadata json.JSON, result *roachpb.CollectedStatementStatistics,
+) error {
+	return (*stmtStatsMetadata)(result).jsonFields().decodeJSON(metadata)
+}
+
+// DecodeStmtStatsStatisticsJSON decodes the 'statistics' field and the
+// 'execution_statistics' field in the given json into
+// roachpb.StatementStatistics.
+func DecodeStmtStatsStatisticsJSON(jsonVal json.JSON, result *roachpb.StatementStatistics) error {
+	return (*stmtStats)(result).decodeJSON(jsonVal)
+}