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)
}
}