github.com/whtcorpsinc/MilevaDB-Prod@v0.0.0-20211104133533-f57f4be3b597/causetstore/petri/schema_checker.go (about)

     1  // Copyright 2020 WHTCORPS INC, Inc.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package petri
    15  
    16  import (
    17  	"sync/atomic"
    18  	"time"
    19  
    20  	"github.com/whtcorpsinc/milevadb/metrics"
    21  	"github.com/whtcorpsinc/milevadb/causetstore/einsteindb"
    22  )
    23  
    24  // SchemaChecker is used for checking schemaReplicant-validity.
    25  type SchemaChecker struct {
    26  	SchemaValidator
    27  	schemaVer       int64
    28  	relatedBlockIDs []int64
    29  }
    30  
    31  type intSchemaVer int64
    32  
    33  func (i intSchemaVer) SchemaMetaVersion() int64 {
    34  	return int64(i)
    35  }
    36  
    37  var (
    38  	// SchemaOutOfDateRetryInterval is the backoff time before retrying.
    39  	SchemaOutOfDateRetryInterval = int64(500 * time.Millisecond)
    40  	// SchemaOutOfDateRetryTimes is the max retry count when the schemaReplicant is out of date.
    41  	SchemaOutOfDateRetryTimes = int32(10)
    42  )
    43  
    44  // NewSchemaChecker creates a new schemaReplicant checker.
    45  func NewSchemaChecker(do *Petri, schemaVer int64, relatedBlockIDs []int64) *SchemaChecker {
    46  	return &SchemaChecker{
    47  		SchemaValidator: do.SchemaValidator,
    48  		schemaVer:       schemaVer,
    49  		relatedBlockIDs: relatedBlockIDs,
    50  	}
    51  }
    52  
    53  // Check checks the validity of the schemaReplicant version.
    54  func (s *SchemaChecker) Check(txnTS uint64) (*einsteindb.RelatedSchemaChange, error) {
    55  	return s.CheckBySchemaVer(txnTS, intSchemaVer(s.schemaVer))
    56  }
    57  
    58  // CheckBySchemaVer checks if the schemaReplicant version valid or not at txnTS.
    59  func (s *SchemaChecker) CheckBySchemaVer(txnTS uint64, startSchemaVer einsteindb.SchemaVer) (*einsteindb.RelatedSchemaChange, error) {
    60  	schemaOutOfDateRetryInterval := atomic.LoadInt64(&SchemaOutOfDateRetryInterval)
    61  	schemaOutOfDateRetryTimes := int(atomic.LoadInt32(&SchemaOutOfDateRetryTimes))
    62  	for i := 0; i < schemaOutOfDateRetryTimes; i++ {
    63  		relatedChange, CheckResult := s.SchemaValidator.Check(txnTS, startSchemaVer.SchemaMetaVersion(), s.relatedBlockIDs)
    64  		switch CheckResult {
    65  		case ResultSucc:
    66  			return nil, nil
    67  		case ResultFail:
    68  			metrics.SchemaLeaseErrorCounter.WithLabelValues("changed").Inc()
    69  			return relatedChange, ErrSchemaReplicantChanged
    70  		case ResultUnknown:
    71  			time.Sleep(time.Duration(schemaOutOfDateRetryInterval))
    72  		}
    73  
    74  	}
    75  	metrics.SchemaLeaseErrorCounter.WithLabelValues("outdated").Inc()
    76  	return nil, ErrSchemaReplicantExpired
    77  }