tidb kv_exec_count 源码
tidb kv_exec_count 代码
文件路径：/util/topsql/stmtstats/kv_exec_count.go
// Copyright 2021 PingCAP, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package stmtstats
import (
"sync"
topsqlstate "github.com/pingcap/tidb/util/topsql/state"
"github.com/tikv/client-go/v2/tikvrpc"
"github.com/tikv/client-go/v2/tikvrpc/interceptor"
)
// CreateKvExecCounter creates an associated KvExecCounter from StatementStats.
// The created KvExecCounter can only be used during a single statement execution
// and cannot be reused.
func (s *StatementStats) CreateKvExecCounter(sqlDigest, planDigest []byte) *KvExecCounter {
return &KvExecCounter{
stats: s,
digest: SQLPlanDigest{SQLDigest: BinaryDigest(sqlDigest), PlanDigest: BinaryDigest(planDigest)},
marked: map[string]struct{}{},
}
}
// KvExecCounter is used to count the number of SQL executions of the kv layer.
// It internally calls addKvExecCount of StatementStats at the right time, to
// ensure the semantic of "SQL execution count of TiKV".
type KvExecCounter struct {
stats *StatementStats
marked map[string]struct{} // HashSet<Target>
digest SQLPlanDigest
mu sync.Mutex
}
// RPCInterceptor returns an interceptor.RPCInterceptor for client-go.
// The returned interceptor is generally expected to be bind to transaction or
// snapshot. In this way, the logic preset by KvExecCounter will be executed before
// each RPC request is initiated, in order to count the number of SQL executions of
// the TiKV dimension.
func (c *KvExecCounter) RPCInterceptor() interceptor.RPCInterceptor {
return func(next interceptor.RPCInterceptorFunc) interceptor.RPCInterceptorFunc {
return func(target string, req *tikvrpc.Request) (*tikvrpc.Response, error) {
if topsqlstate.TopSQLEnabled() {
c.mark(target)
}
return next(target, req)
}
}
}
// mark this target during the current execution of statement.
// If this target is marked for the first time, then increase the number of execution.
// mark is thread-safe.
func (c *KvExecCounter) mark(target string) {
firstMark := false
c.mu.Lock()
if _, ok := c.marked[target]; !ok {
c.marked[target] = struct{}{}
firstMark = true
}
c.mu.Unlock()
if firstMark {
c.stats.addKvExecCount([]byte(c.digest.SQLDigest), []byte(c.digest.PlanDigest), target, 1)
}
}
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