executor: use a hash for plan cache keys

Signed-off-by: Vicent Marti <[email protected]>

go/vt/vtgate/executor.go

@@ -19,6 +19,8 @@ package vtgate
 import (
 	"bytes"
 	"context"
+	"crypto/sha256"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -31,6 +33,7 @@ import (
 
 	"vitess.io/vitess/go/acl"
 	"vitess.io/vitess/go/cache"
+	"vitess.io/vitess/go/hack"
 	"vitess.io/vitess/go/mysql"
 	"vitess.io/vitess/go/sqltypes"
 	"vitess.io/vitess/go/stats"
@@ -1235,7 +1238,12 @@ func (e *Executor) getPlan(vcursor *vcursorImpl, sql string, comments sqlparser.
 		logStats.BindVariables = bindVars
 	}
 
-	planKey := vcursor.planPrefixKey() + ":" + query
+	planHash := sha256.New()
+	planHash.Write([]byte(vcursor.planPrefixKey()))
+	planHash.Write([]byte{':'})
+	planHash.Write(hack.StringBytes(query))
+	planKey := hex.EncodeToString(planHash.Sum(nil))
+
 	if plan, ok := e.plans.Get(planKey); ok {
 		return plan.(*engine.Plan), nil
 	}
@@ -1255,6 +1263,15 @@ func (e *Executor) getPlan(vcursor *vcursorImpl, sql string, comments sqlparser.
 	return e.checkThatPlanIsValid(stmt, plan)
 }
 
+func (e *Executor) debugGetPlan(planKey string) (*engine.Plan, bool) {
+	planHash := sha256.Sum256([]byte(planKey))
+	planHex := hex.EncodeToString(planHash[:])
+	if plan, ok := e.plans.Get(planHex); ok {
+		return plan.(*engine.Plan), true
+	}
+	return nil, false
+}
+
 // skipQueryPlanCache extracts SkipQueryPlanCache from session
 func skipQueryPlanCache(safeSession *SafeSession) bool {
 	if safeSession == nil || safeSession.Options == nil {

go/vt/vtgate/executor_test.go

@@ -1464,7 +1464,7 @@ func TestGetPlanUnnormalized(t *testing.T) {
 	want := []string{
 		"@unknown:" + query1,
 	}
-	assertCacheContains(t, r.plans, want)
+	assertCacheContains(t, r, want)
 	if logStats2.SQL != wantSQL {
 		t.Errorf("logstats sql want \"%s\" got \"%s\"", wantSQL, logStats2.SQL)
 	}
@@ -1483,7 +1483,7 @@ func TestGetPlanUnnormalized(t *testing.T) {
 		KsTestUnsharded + "@unknown:" + query1,
 		"@unknown:" + query1,
 	}
-	assertCacheContains(t, r.plans, want)
+	assertCacheContains(t, r, want)
 	if logStats4.SQL != wantSQL {
 		t.Errorf("logstats sql want \"%s\" got \"%s\"", wantSQL, logStats4.SQL)
 	}
@@ -1501,10 +1501,10 @@ func assertCacheSize(t *testing.T, c cache.Cache, expected int) {
 	}
 }
 
-func assertCacheContains(t *testing.T, c cache.Cache, want []string) {
+func assertCacheContains(t *testing.T, e *Executor, want []string) {
 	t.Helper()
 	for _, wantKey := range want {
-		if _, ok := c.Get(wantKey); !ok {
+		if _, ok := e.debugGetPlan(wantKey); !ok {
 			t.Errorf("missing key in plan cache: %v", wantKey)
 		}
 	}
@@ -1626,7 +1626,7 @@ func TestGetPlanNormalized(t *testing.T) {
 	want := []string{
 		"@unknown:" + normalized,
 	}
-	assertCacheContains(t, r.plans, want)
+	assertCacheContains(t, r, want)
 
 	wantSQL := normalized + " /* comment 1 */"
 	if logStats1.SQL != wantSQL {
@@ -1673,14 +1673,14 @@ func TestGetPlanNormalized(t *testing.T) {
 		KsTestUnsharded + "@unknown:" + normalized,
 		"@unknown:" + normalized,
 	}
-	assertCacheContains(t, r.plans, want)
+	assertCacheContains(t, r, want)
 
 	_, err := r.getPlan(emptyvc, "syntax", makeComments(""), map[string]*querypb.BindVariable{}, false, nil)
 	wantErr := "syntax error at position 7 near 'syntax'"
 	if err == nil || err.Error() != wantErr {
 		t.Errorf("getPlan(syntax): %v, want %s", err, wantErr)
 	}
-	assertCacheContains(t, r.plans, want)
+	assertCacheContains(t, r, want)
 }
 
 func TestPassthroughDDL(t *testing.T) {

go/vt/vtgate/queryz_test.go

@@ -44,23 +44,21 @@ func TestQueryzHandler(t *testing.T) {
 	_, err := executorExec(executor, sql, nil)
 	require.NoError(t, err)
 	executor.plans.Wait()
-	result, ok := executor.plans.Get("@primary:" + sql)
+	plan1, ok := executor.debugGetPlan("@primary:" + sql)
 	if !ok {
 		t.Fatalf("couldn't get plan from cache")
 	}
-	plan1 := result.(*engine.Plan)
 	plan1.ExecTime = uint64(1 * time.Millisecond)
 
 	// scatter
 	sql = "select id from user"
 	_, err = executorExec(executor, sql, nil)
 	require.NoError(t, err)
 	executor.plans.Wait()
-	result, ok = executor.plans.Get("@primary:" + sql)
+	plan2, ok := executor.debugGetPlan("@primary:" + sql)
 	if !ok {
 		t.Fatalf("couldn't get plan from cache")
 	}
-	plan2 := result.(*engine.Plan)
 	plan2.ExecTime = uint64(1 * time.Second)
 
 	sql = "insert into user (id, name) values (:id, :name)"
@@ -70,18 +68,15 @@ func TestQueryzHandler(t *testing.T) {
 	})
 	require.NoError(t, err)
 	executor.plans.Wait()
-	result, ok = executor.plans.Get("@primary:" + sql)
+	plan3, ok := executor.debugGetPlan("@primary:" + sql)
 	if !ok {
 		t.Fatalf("couldn't get plan from cache")
 	}
-	plan3 := result.(*engine.Plan)
 
 	// vindex insert from above execution
-	result, ok = executor.plans.Get("@primary:" + "insert into name_user_map(name, user_id) values(:name_0, :user_id_0)")
+	plan4, ok := executor.debugGetPlan("@primary:" + "insert into name_user_map(name, user_id) values(:name_0, :user_id_0)")
 	require.True(t, ok, "couldn't get plan from cache")
 
-	plan4 := result.(*engine.Plan)
-
 	// same query again should add query counts to existing plans
 	sql = "insert into user (id, name) values (:id, :name)"
 	_, err = executorExec(executor, sql, map[string]*querypb.BindVariable{