planner: refactor plan cache LRU code (#41618)

ref #40219

planner/core/BUILD.bazel

@@ -133,6 +133,7 @@ go_library(
         "//util/mock",
         "//util/paging",
         "//util/parser",
+        "//util/plancache",
         "//util/plancodec",
         "//util/ranger",
         "//util/rowcodec",
@@ -260,6 +261,7 @@ go_test(
         "//util/kvcache",
         "//util/logutil",
         "//util/mock",
+        "//util/plancache",
         "//util/plancodec",
         "//util/ranger",
         "//util/set",

planner/core/plan_cache.go

@@ -38,6 +38,7 @@ import (
 	"github.com/pingcap/tidb/util/collate"
 	"github.com/pingcap/tidb/util/kvcache"
 	"github.com/pingcap/tidb/util/logutil"
+	utilpc "github.com/pingcap/tidb/util/plancache"
 	"github.com/pingcap/tidb/util/ranger"
 	"go.uber.org/zap"
 )
@@ -158,25 +159,23 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
 		}
 	}
 
-	paramTypes := parseParamTypes(sctx, params)
-
 	if stmtCtx.UseCache && stmtAst.CachedPlan != nil { // special code path for fast point plan
 		if plan, names, ok, err := getCachedPointPlan(stmtAst, sessVars, stmtCtx); ok {
 			return plan, names, err
 		}
 	}
-	limitCountAndOffset, paramErr := ExtractLimitFromAst(stmt.PreparedAst.Stmt, sctx)
-	if paramErr != nil {
-		return nil, nil, paramErr
+
+	matchOpts, err := GetMatchOpts(sctx, stmt.PreparedAst.Stmt, params)
+	if err != nil {
+		return nil, nil, err
 	}
 	if stmtCtx.UseCache { // for non-point plans
-		if plan, names, ok, err := getCachedPlan(sctx, isNonPrepared, cacheKey, bindSQL, is, stmt,
-			paramTypes, limitCountAndOffset); err != nil || ok {
+		if plan, names, ok, err := getCachedPlan(sctx, isNonPrepared, cacheKey, bindSQL, is, stmt, matchOpts); err != nil || ok {
 			return plan, names, err
 		}
 	}
 
-	return generateNewPlan(ctx, sctx, isNonPrepared, is, stmt, cacheKey, latestSchemaVersion, paramTypes, bindSQL, limitCountAndOffset)
+	return generateNewPlan(ctx, sctx, isNonPrepared, is, stmt, cacheKey, latestSchemaVersion, bindSQL, matchOpts)
 }
 
 // parseParamTypes get parameters' types in PREPARE statement
@@ -223,12 +222,12 @@ func getCachedPointPlan(stmt *ast.Prepared, sessVars *variable.SessionVars, stmt
 }
 
 func getCachedPlan(sctx sessionctx.Context, isNonPrepared bool, cacheKey kvcache.Key, bindSQL string,
-	is infoschema.InfoSchema, stmt *PlanCacheStmt, paramTypes []*types.FieldType, limitParams []uint64) (Plan,
+	is infoschema.InfoSchema, stmt *PlanCacheStmt, matchOpts *utilpc.PlanCacheMatchOpts) (Plan,
 	[]*types.FieldName, bool, error) {
 	sessVars := sctx.GetSessionVars()
 	stmtCtx := sessVars.StmtCtx
 
-	candidate, exist := sctx.GetPlanCache(isNonPrepared).Get(cacheKey, paramTypes, limitParams)
+	candidate, exist := sctx.GetPlanCache(isNonPrepared).Get(cacheKey, matchOpts)
 	if !exist {
 		return nil, nil, false, nil
 	}
@@ -267,8 +266,8 @@ func getCachedPlan(sctx sessionctx.Context, isNonPrepared bool, cacheKey kvcache
 // generateNewPlan call the optimizer to generate a new plan for current statement
 // and try to add it to cache
 func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isNonPrepared bool, is infoschema.InfoSchema,
-	stmt *PlanCacheStmt, cacheKey kvcache.Key, latestSchemaVersion int64, paramTypes []*types.FieldType,
-	bindSQL string, limitParams []uint64) (Plan, []*types.FieldName, error) {
+	stmt *PlanCacheStmt, cacheKey kvcache.Key, latestSchemaVersion int64, bindSQL string,
+	matchOpts *utilpc.PlanCacheMatchOpts) (Plan, []*types.FieldName, error) {
 	stmtAst := stmt.PreparedAst
 	sessVars := sctx.GetSessionVars()
 	stmtCtx := sessVars.StmtCtx
@@ -287,7 +286,7 @@ func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isNonPrepared
 
 	// check whether this plan is cacheable.
 	if stmtCtx.UseCache {
-		if cacheable, reason := isPlanCacheable(sctx, p, len(paramTypes), len(limitParams)); !cacheable {
+		if cacheable, reason := isPlanCacheable(sctx, p, len(matchOpts.ParamTypes), len(matchOpts.LimitOffsetAndCount)); !cacheable {
 			stmtCtx.SetSkipPlanCache(errors.Errorf(reason))
 		}
 	}
@@ -303,11 +302,11 @@ func generateNewPlan(ctx context.Context, sctx sessionctx.Context, isNonPrepared
 			}
 			sessVars.IsolationReadEngines[kv.TiFlash] = struct{}{}
 		}
-		cached := NewPlanCacheValue(p, names, stmtCtx.TblInfo2UnionScan, paramTypes, limitParams)
+		cached := NewPlanCacheValue(p, names, stmtCtx.TblInfo2UnionScan, matchOpts)
 		stmt.NormalizedPlan, stmt.PlanDigest = NormalizePlan(p)
 		stmtCtx.SetPlan(p)
 		stmtCtx.SetPlanDigest(stmt.NormalizedPlan, stmt.PlanDigest)
-		sctx.GetPlanCache(isNonPrepared).Put(cacheKey, cached, paramTypes, limitParams)
+		sctx.GetPlanCache(isNonPrepared).Put(cacheKey, cached, matchOpts)
 	}
 	sessVars.FoundInPlanCache = false
 	return p, names, err

planner/core/plan_cache_lru.go

@@ -20,11 +20,11 @@ import (
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/metrics"
 	"github.com/pingcap/tidb/sessionctx"
-	"github.com/pingcap/tidb/types"
 	"github.com/pingcap/tidb/util/hack"
 	"github.com/pingcap/tidb/util/kvcache"
 	"github.com/pingcap/tidb/util/logutil"
 	"github.com/pingcap/tidb/util/memory"
+	utilpc "github.com/pingcap/tidb/util/plancache"
 )
 
 // planCacheEntry wraps Key and Value. It's the value of list.Element.
@@ -89,17 +89,13 @@ func strHashKey(key kvcache.Key, deepCopy bool) string {
 }
 
 // Get tries to find the corresponding value according to the given key.
-func (l *LRUPlanCache) Get(key kvcache.Key, paramTypes []*types.FieldType, limitParams []uint64) (value kvcache.Value, ok bool) {
+func (l *LRUPlanCache) Get(key kvcache.Key, opts *utilpc.PlanCacheMatchOpts) (value kvcache.Value, ok bool) {
 	l.lock.Lock()
 	defer l.lock.Unlock()
 
 	bucket, bucketExist := l.buckets[strHashKey(key, false)]
 	if bucketExist {
-		matchOpts := &planCacheMatchOpts{
-			paramTypes:          paramTypes,
-			limitOffsetAndCount: limitParams,
-		}
-		if element, exist := l.pickFromBucket(bucket, matchOpts); exist {
+		if element, exist := l.pickFromBucket(bucket, opts); exist {
 			l.lruList.MoveToFront(element)
 			return element.Value.(*planCacheEntry).PlanValue, true
 		}
@@ -108,18 +104,14 @@ func (l *LRUPlanCache) Get(key kvcache.Key, paramTypes []*types.FieldType, limit
 }
 
 // Put puts the (key, value) pair into the LRU Cache.
-func (l *LRUPlanCache) Put(key kvcache.Key, value kvcache.Value, paramTypes []*types.FieldType, limitParams []uint64) {
+func (l *LRUPlanCache) Put(key kvcache.Key, value kvcache.Value, opts *utilpc.PlanCacheMatchOpts) {
 	l.lock.Lock()
 	defer l.lock.Unlock()
 
 	hash := strHashKey(key, true)
 	bucket, bucketExist := l.buckets[hash]
 	if bucketExist {
-		matchOpts := &planCacheMatchOpts{
-			paramTypes:          paramTypes,
-			limitOffsetAndCount: limitParams,
-		}
-		if element, exist := l.pickFromBucket(bucket, matchOpts); exist {
+		if element, exist := l.pickFromBucket(bucket, opts); exist {
 			l.updateInstanceMetric(&planCacheEntry{PlanKey: key, PlanValue: value}, element.Value.(*planCacheEntry))
 			element.Value.(*planCacheEntry).PlanValue = value
 			l.lruList.MoveToFront(element)
@@ -255,21 +247,21 @@ func (l *LRUPlanCache) memoryControl() {
 }
 
 // PickPlanFromBucket pick one plan from bucket
-func (l *LRUPlanCache) pickFromBucket(bucket map[*list.Element]struct{}, matchOpts *planCacheMatchOpts) (*list.Element, bool) {
+func (l *LRUPlanCache) pickFromBucket(bucket map[*list.Element]struct{}, matchOpts *utilpc.PlanCacheMatchOpts) (*list.Element, bool) {
 	for k := range bucket {
 		plan := k.Value.(*planCacheEntry).PlanValue.(*PlanCacheValue)
 		// check param types' compatibility
-		ok1 := plan.matchOpts.paramTypes.CheckTypesCompatibility4PC(matchOpts.paramTypes)
+		ok1 := checkTypesCompatibility4PC(plan.matchOpts.ParamTypes, matchOpts.ParamTypes)
 		if !ok1 {
 			continue
 		}
 
 		// check limit offset and key if equal and check switch if enabled
-		ok2 := checkUint64SliceIfEqual(plan.matchOpts.limitOffsetAndCount, matchOpts.limitOffsetAndCount)
+		ok2 := checkUint64SliceIfEqual(plan.matchOpts.LimitOffsetAndCount, matchOpts.LimitOffsetAndCount)
 		if !ok2 {
 			continue
 		}
-		if len(plan.matchOpts.limitOffsetAndCount) > 0 && !l.sctx.GetSessionVars().EnablePlanCacheForParamLimit {
+		if len(plan.matchOpts.LimitOffsetAndCount) > 0 && !l.sctx.GetSessionVars().EnablePlanCacheForParamLimit {
 			// offset and key slice matched, but it is a plan with param limit and the switch is disabled
 			continue
 		}