sql: plumb tracer explicitly through EvalCtx

Some builtins needed the Tracer and was accessing it through the Settings.
I'm trying to untangle the Tracer from the Settings. This patch passes
the Tracer through the EvalCtx.

Release note: None

pkg/sql/conn_executor.go

@@ -2447,6 +2447,7 @@ func (ex *connExecutor) initEvalCtx(ctx context.Context, evalCtx *extendedEvalCo
 			NodeID:                 ex.server.cfg.NodeID,
 			Codec:                  ex.server.cfg.Codec,
 			Locality:               ex.server.cfg.Locality,
+			Tracer:                 ex.server.cfg.AmbientCtx.Tracer,
 			ReCache:                ex.server.reCache,
 			InternalExecutor:       &ie,
 			DB:                     ex.server.cfg.DB,

pkg/sql/distsql/server.go

@@ -349,6 +349,7 @@ func (ds *ServerImpl) setupFlow(
 			ReCache:          ds.regexpCache,
 			Mon:              monitor,
 			Locality:         ds.ServerConfig.Locality,
+			Tracer:           ds.ServerConfig.Tracer,
 			// Most processors will override this Context with their own context in
 			// ProcessorBase. StartInternal().
 			Context:            ctx,

pkg/sql/planner.go

@@ -452,6 +452,7 @@ func internalExtendedEvalCtx(
 			TxnImplicit:        true,
 			Settings:           execCfg.Settings,
 			Codec:              execCfg.Codec,
+			Tracer:             execCfg.AmbientCtx.Tracer,
 			Context:            ctx,
 			Mon:                plannerMon,
 			TestingKnobs:       evalContextTestingKnobs,

pkg/sql/schema_changer.go

@@ -2023,6 +2023,7 @@ func createSchemaChangeEvalCtx(
 			NodeID:             execCfg.NodeID,
 			Codec:              execCfg.Codec,
 			Locality:           execCfg.Locality,
+			Tracer:             execCfg.AmbientCtx.Tracer,
 		},
 	}
 	// The backfill is going to use the current timestamp for the various

pkg/sql/sem/builtins/builtins.go

@@ -4330,7 +4330,10 @@ value if you rely on the HLC for accuracy.`,
 				verbosity := bool(*(args[1].(*tree.DBool)))
 
 				var rootSpan *tracing.Span
-				if err := ctx.Settings.Tracer.VisitSpans(func(span *tracing.Span) error {
+				if ctx.Tracer == nil {
+					return nil, errors.AssertionFailedf("Tracer not configured")
+				}
+				if err := ctx.Tracer.VisitSpans(func(span *tracing.Span) error {
 					if span.TraceID() == traceID && rootSpan == nil {
 						rootSpan = span
 					}

pkg/sql/sem/builtins/generator_builtins.go

@@ -1705,7 +1705,7 @@ func makePayloadsForSpanGenerator(
 		)
 	}
 	spanID := uint64(*(args[0].(*tree.DInt)))
-	span, found := ctx.Settings.Tracer.GetActiveSpanFromID(spanID)
+	span, found := ctx.Tracer.GetActiveSpanFromID(spanID)
 	if !found {
 		return nil, nil
 	}

pkg/sql/sem/tree/BUILD.bazel

@@ -159,6 +159,7 @@ go_library(
         "//pkg/util/timetz",
         "//pkg/util/timeutil",
         "//pkg/util/timeutil/pgdate",
+        "//pkg/util/tracing",
         "//pkg/util/uint128",
         "//pkg/util/uuid",
         "@com_github_cockroachdb_apd_v2//:apd",

pkg/sql/sem/tree/eval.go

@@ -48,6 +48,7 @@ import (
 	"github.com/cockroachdb/cockroach/pkg/util/timeofday"
 	"github.com/cockroachdb/cockroach/pkg/util/timeutil"
 	"github.com/cockroachdb/cockroach/pkg/util/timeutil/pgdate"
+	"github.com/cockroachdb/cockroach/pkg/util/tracing"
 	"github.com/cockroachdb/cockroach/pkg/util/uuid"
 	"github.com/cockroachdb/errors"
 	"github.com/lib/pq/oid"
@@ -3482,6 +3483,8 @@ type EvalContext struct {
 	//
 	Locality roachpb.Locality
 
+	Tracer *tracing.Tracer
+
 	// The statement timestamp. May be different for every statement.
 	// Used for statement_timestamp().
 	StmtTimestamp time.Time