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planner: refactor a few code of plan cache #54075

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merged 10 commits into from
Jun 18, 2024
Merged

planner: refactor a few code of plan cache #54075

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69cdcd4
fixup
qw4990 Jun 17, 2024
06ef94d
fixup
qw4990 Jun 17, 2024
198a3e6
fixup
qw4990 Jun 18, 2024
393d558
Merge remote-tracking branch 'upstream/master' into plan-cache-string…
qw4990 Jun 18, 2024
634fcfb
fixup
qw4990 Jun 18, 2024
a35de45
fixup
qw4990 Jun 18, 2024
21b0e8c
fixup
qw4990 Jun 18, 2024
fb24470
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qw4990 Jun 18, 2024
71b6a82
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qw4990 Jun 18, 2024
a1353da
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qw4990 Jun 18, 2024
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4 changes: 0 additions & 4 deletions pkg/planner/core/BUILD.bazel
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Original file line number Diff line number Diff line change
Expand Up @@ -168,7 +168,6 @@ go_library(
"//pkg/util/mock",
"//pkg/util/paging",
"//pkg/util/parser",
"//pkg/util/plancache",
"//pkg/util/plancodec",
"//pkg/util/ranger",
"//pkg/util/ranger/context",
Expand Down Expand Up @@ -292,12 +291,9 @@ go_test(
"//pkg/util/context",
"//pkg/util/dbterror",
"//pkg/util/dbterror/plannererrors",
"//pkg/util/hack",
"//pkg/util/hint",
"//pkg/util/kvcache",
"//pkg/util/logutil",
"//pkg/util/mock",
"//pkg/util/plancache",
"//pkg/util/plancodec",
"//pkg/util/ranger",
"//pkg/util/set",
Expand Down
11 changes: 5 additions & 6 deletions pkg/planner/core/plan_cache.go
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,6 @@ import (
contextutil "github.com/pingcap/tidb/pkg/util/context"
"github.com/pingcap/tidb/pkg/util/dbterror/plannererrors"
"github.com/pingcap/tidb/pkg/util/kvcache"
utilpc "github.com/pingcap/tidb/pkg/util/plancache"
)

// PlanCacheKeyTestIssue43667 is only for test.
Expand Down Expand Up @@ -174,7 +173,7 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
return nil, nil, err
}

var cacheKey kvcache.Key
var cacheKey string
sessVars := sctx.GetSessionVars()
stmtCtx := sessVars.StmtCtx
cacheEnabled := false
Expand Down Expand Up @@ -218,7 +217,7 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
}
}

var matchOpts *utilpc.PlanCacheMatchOpts
var matchOpts *PlanCacheMatchOpts
if stmtCtx.UseCache() {
var cacheVal kvcache.Value
var hit, isPointPlan bool
Expand Down Expand Up @@ -247,7 +246,7 @@ func GetPlanFromSessionPlanCache(ctx context.Context, sctx sessionctx.Context,
}

func adjustCachedPlan(sctx sessionctx.Context, cachedVal *PlanCacheValue, isNonPrepared, isPointPlan bool,
cacheKey kvcache.Key, bindSQL string, is infoschema.InfoSchema, stmt *PlanCacheStmt) (base.Plan,
cacheKey string, bindSQL string, is infoschema.InfoSchema, stmt *PlanCacheStmt) (base.Plan,
[]*types.FieldName, bool, error) {
sessVars := sctx.GetSessionVars()
stmtCtx := sessVars.StmtCtx
Expand Down Expand Up @@ -286,8 +285,8 @@ func adjustCachedPlan(sctx sessionctx.Context, cachedVal *PlanCacheValue, isNonP
// 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, bindSQL string,
matchOpts *utilpc.PlanCacheMatchOpts) (base.Plan, []*types.FieldName, error) {
stmt *PlanCacheStmt, cacheKey string, latestSchemaVersion int64, bindSQL string,
matchOpts *PlanCacheMatchOpts) (base.Plan, []*types.FieldName, error) {
stmtAst := stmt.PreparedAst
sessVars := sctx.GetSessionVars()
stmtCtx := sessVars.StmtCtx
Expand Down
44 changes: 18 additions & 26 deletions pkg/planner/core/plan_cache_lru.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,17 +19,15 @@ import (
"github.com/pingcap/errors"
core_metrics "github.com/pingcap/tidb/pkg/planner/core/metrics"
"github.com/pingcap/tidb/pkg/sessionctx"
"github.com/pingcap/tidb/pkg/util/hack"
"github.com/pingcap/tidb/pkg/util/kvcache"
"github.com/pingcap/tidb/pkg/util/logutil"
"github.com/pingcap/tidb/pkg/util/memory"
utilpc "github.com/pingcap/tidb/pkg/util/plancache"
"github.com/pingcap/tidb/pkg/util/syncutil"
)

// planCacheEntry wraps Key and Value. It's the value of list.Element.
type planCacheEntry struct {
PlanKey kvcache.Key
PlanKey string
PlanValue kvcache.Value
}

Expand All @@ -39,7 +37,7 @@ func (e *planCacheEntry) MemoryUsage() (sum int64) {
return
}

return e.PlanKey.(*planCacheKey).MemoryUsage() + e.PlanValue.(*PlanCacheValue).MemoryUsage()
return int64(len(e.PlanKey)) + e.PlanValue.(*PlanCacheValue).MemoryUsage()
}

// LRUPlanCache is a dedicated least recently used cache, Only used for plan cache.
Expand All @@ -52,7 +50,7 @@ type LRUPlanCache struct {
// lock make cache thread safe
lock syncutil.RWMutex
// onEvict will be called if any eviction happened, only for test use now
onEvict func(kvcache.Key, kvcache.Value)
onEvict func(string, any)

// 0 indicates no quota
quota uint64
Expand Down Expand Up @@ -80,20 +78,12 @@ func NewLRUPlanCache(capacity uint, guard float64, quota uint64, sctx sessionctx
}
}

// strHashKey control deep or Shallow copy of string
func strHashKey(key kvcache.Key, deepCopy bool) string {
if deepCopy {
return string(key.Hash())
}
return string(hack.String(key.Hash()))
}

// Get tries to find the corresponding value according to the given key.
func (l *LRUPlanCache) Get(key kvcache.Key, opts *utilpc.PlanCacheMatchOpts) (value kvcache.Value, ok bool) {
func (l *LRUPlanCache) Get(key string, opts any) (value any, ok bool) {
l.lock.RLock()
defer l.lock.RUnlock()

bucket, bucketExist := l.buckets[strHashKey(key, false)]
bucket, bucketExist := l.buckets[key]
if bucketExist {
if element, exist := l.pickFromBucket(bucket, opts); exist {
l.lruList.MoveToFront(element)
Expand All @@ -104,12 +94,11 @@ func (l *LRUPlanCache) Get(key kvcache.Key, opts *utilpc.PlanCacheMatchOpts) (va
}

// Put puts the (key, value) pair into the LRU Cache.
func (l *LRUPlanCache) Put(key kvcache.Key, value kvcache.Value, opts *utilpc.PlanCacheMatchOpts) {
func (l *LRUPlanCache) Put(key string, value, opts any) {
l.lock.Lock()
defer l.lock.Unlock()

hash := strHashKey(key, true)
bucket, bucketExist := l.buckets[hash]
bucket, bucketExist := l.buckets[key]
if bucketExist {
if element, exist := l.pickFromBucket(bucket, opts); exist {
l.updateInstanceMetric(&planCacheEntry{PlanKey: key, PlanValue: value}, element.Value.(*planCacheEntry))
Expand All @@ -118,15 +107,15 @@ func (l *LRUPlanCache) Put(key kvcache.Key, value kvcache.Value, opts *utilpc.Pl
return
}
} else {
l.buckets[hash] = make(map[*list.Element]struct{}, 1)
l.buckets[key] = make(map[*list.Element]struct{}, 1)
}

newCacheEntry := &planCacheEntry{
PlanKey: key,
PlanValue: value,
}
element := l.lruList.PushFront(newCacheEntry)
l.buckets[hash][element] = struct{}{}
l.buckets[key][element] = struct{}{}
l.size++
l.updateInstanceMetric(newCacheEntry, nil)
if l.size > l.capacity {
Expand All @@ -136,19 +125,18 @@ func (l *LRUPlanCache) Put(key kvcache.Key, value kvcache.Value, opts *utilpc.Pl
}

// Delete deletes the multi-values from the LRU Cache.
func (l *LRUPlanCache) Delete(key kvcache.Key) {
func (l *LRUPlanCache) Delete(key string) {
l.lock.Lock()
defer l.lock.Unlock()

hash := strHashKey(key, false)
bucket, bucketExist := l.buckets[hash]
bucket, bucketExist := l.buckets[key]
if bucketExist {
for element := range bucket {
l.updateInstanceMetric(nil, element.Value.(*planCacheEntry))
l.lruList.Remove(element)
l.size--
}
delete(l.buckets, hash)
delete(l.buckets, key)
}
}

Expand Down Expand Up @@ -229,7 +217,7 @@ func (l *LRUPlanCache) removeOldest() {

// removeFromBucket remove element from bucket
func (l *LRUPlanCache) removeFromBucket(element *list.Element) {
hash := strHashKey(element.Value.(*planCacheEntry).PlanKey, false)
hash := element.Value.(*planCacheEntry).PlanKey
bucket := l.buckets[hash]
delete(bucket, element)
if len(bucket) == 0 {
Expand All @@ -251,7 +239,11 @@ func (l *LRUPlanCache) memoryControl() {
}

// PickPlanFromBucket pick one plan from bucket
func (l *LRUPlanCache) pickFromBucket(bucket map[*list.Element]struct{}, matchOpts *utilpc.PlanCacheMatchOpts) (*list.Element, bool) {
func (l *LRUPlanCache) pickFromBucket(bucket map[*list.Element]struct{}, opts any) (*list.Element, bool) {
var matchOpts *PlanCacheMatchOpts
if opts != nil {
matchOpts = opts.(*PlanCacheMatchOpts)
}
for k := range bucket {
if matchCachedPlan(l.sctx, k.Value.(*planCacheEntry).PlanValue.(*PlanCacheValue), matchOpts) {
return k, true
Expand Down
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