255 lines
10 KiB
Go
255 lines
10 KiB
Go
// Copyright 2018 PingCAP, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package sessionctx
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import (
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"context"
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"time"
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"github.com/pingcap/errors"
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"github.com/pingcap/kvproto/pkg/kvrpcpb"
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distsqlctx "github.com/pingcap/tidb/pkg/distsql/context"
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exprctx "github.com/pingcap/tidb/pkg/expression/context"
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"github.com/pingcap/tidb/pkg/extension"
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infoschema "github.com/pingcap/tidb/pkg/infoschema/context"
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"github.com/pingcap/tidb/pkg/kv"
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tablelock "github.com/pingcap/tidb/pkg/lock/context"
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"github.com/pingcap/tidb/pkg/metrics"
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"github.com/pingcap/tidb/pkg/parser/model"
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planctx "github.com/pingcap/tidb/pkg/planner/context"
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"github.com/pingcap/tidb/pkg/sessionctx/sessionstates"
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"github.com/pingcap/tidb/pkg/sessionctx/stmtctx"
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"github.com/pingcap/tidb/pkg/sessionctx/variable"
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"github.com/pingcap/tidb/pkg/statistics/handle/usage/indexusage"
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tbctx "github.com/pingcap/tidb/pkg/table/context"
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"github.com/pingcap/tidb/pkg/util"
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contextutil "github.com/pingcap/tidb/pkg/util/context"
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"github.com/pingcap/tidb/pkg/util/kvcache"
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utilpc "github.com/pingcap/tidb/pkg/util/plancache"
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"github.com/pingcap/tidb/pkg/util/sli"
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"github.com/pingcap/tidb/pkg/util/sqlexec"
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"github.com/pingcap/tidb/pkg/util/topsql/stmtstats"
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"github.com/pingcap/tipb/go-binlog"
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"github.com/tikv/client-go/v2/oracle"
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)
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// SessionStatesHandler is an interface for encoding and decoding session states.
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type SessionStatesHandler interface {
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// EncodeSessionStates encodes session states into a JSON.
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EncodeSessionStates(context.Context, Context, *sessionstates.SessionStates) error
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// DecodeSessionStates decodes a map into session states.
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DecodeSessionStates(context.Context, Context, *sessionstates.SessionStates) error
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}
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// PlanCache is an interface for prepare and non-prepared plan cache
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type PlanCache interface {
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Get(key kvcache.Key, opts *utilpc.PlanCacheMatchOpts) (value kvcache.Value, ok bool)
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Put(key kvcache.Key, value kvcache.Value, opts *utilpc.PlanCacheMatchOpts)
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Delete(key kvcache.Key)
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DeleteAll()
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Size() int
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SetCapacity(capacity uint) error
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Close()
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}
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// Context is an interface for transaction and executive args environment.
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type Context interface {
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SessionStatesHandler
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contextutil.ValueStoreContext
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tablelock.TableLockContext
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// SetDiskFullOpt set the disk full opt when tikv disk full happened.
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SetDiskFullOpt(level kvrpcpb.DiskFullOpt)
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// ClearDiskFullOpt clear the disk full opt.
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ClearDiskFullOpt()
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// RollbackTxn rolls back the current transaction.
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RollbackTxn(ctx context.Context)
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// CommitTxn commits the current transaction.
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CommitTxn(ctx context.Context) error
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// Txn returns the current transaction which is created before executing a statement.
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// The returned kv.Transaction is not nil, but it maybe pending or invalid.
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// If the active parameter is true, call this function will wait for the pending txn
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// to become valid.
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Txn(active bool) (kv.Transaction, error)
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// GetClient gets a kv.Client.
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GetClient() kv.Client
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// GetMPPClient gets a kv.MPPClient.
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GetMPPClient() kv.MPPClient
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// Deprecated: the semantics of session.GetInfoSchema() is ambiguous
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// If you want to get the infoschema of the current transaction in SQL layer, use sessiontxn.GetTxnManager(ctx).GetTxnInfoSchema()
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// If you want to get the latest infoschema use `GetDomainInfoSchema`
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GetInfoSchema() infoschema.MetaOnlyInfoSchema
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// GetDomainInfoSchema returns the latest information schema in domain
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// Different with `domain.InfoSchema()`, the information schema returned by this method
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// includes the temporary table definitions stored in session
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GetDomainInfoSchema() infoschema.MetaOnlyInfoSchema
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GetSessionVars() *variable.SessionVars
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// GetSQLExecutor returns the sqlexec.SQLExecutor.
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GetSQLExecutor() sqlexec.SQLExecutor
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// GetRestrictedSQLExecutor returns the sqlexec.RestrictedSQLExecutor.
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GetRestrictedSQLExecutor() sqlexec.RestrictedSQLExecutor
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// GetExprCtx returns the expression context of the session.
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GetExprCtx() exprctx.BuildContext
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// GetTableCtx returns the table.MutateContext
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GetTableCtx() tbctx.MutateContext
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// GetPlanCtx gets the plan context of the current session.
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GetPlanCtx() planctx.PlanContext
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// GetDistSQLCtx gets the distsql ctx of the current session
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GetDistSQLCtx() distsqlctx.DistSQLContext
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GetSessionManager() util.SessionManager
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// RefreshTxnCtx commits old transaction without retry,
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// and creates a new transaction.
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// now just for load data and batch insert.
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RefreshTxnCtx(context.Context) error
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// GetStore returns the store of session.
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GetStore() kv.Storage
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// GetSessionPlanCache returns the session-level cache of the physical plan.
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GetSessionPlanCache() PlanCache
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// UpdateColStatsUsage updates the column stats usage.
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UpdateColStatsUsage(predicateColumns []model.TableItemID)
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// HasDirtyContent checks whether there's dirty update on the given table.
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HasDirtyContent(tid int64) bool
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// StmtCommit flush all changes by the statement to the underlying transaction.
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StmtCommit(ctx context.Context)
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// StmtRollback provides statement level rollback. The parameter `forPessimisticRetry` should be true iff it's used
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// for auto-retrying execution of DMLs in pessimistic transactions.
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StmtRollback(ctx context.Context, isForPessimisticRetry bool)
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// StmtGetMutation gets the binlog mutation for current statement.
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StmtGetMutation(int64) *binlog.TableMutation
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// IsDDLOwner checks whether this session is DDL owner.
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IsDDLOwner() bool
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// PrepareTSFuture uses to prepare timestamp by future.
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PrepareTSFuture(ctx context.Context, future oracle.Future, scope string) error
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// GetPreparedTxnFuture returns the TxnFuture if it is valid or pending.
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// It returns nil otherwise.
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GetPreparedTxnFuture() TxnFuture
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// GetTxnWriteThroughputSLI returns the TxnWriteThroughputSLI.
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GetTxnWriteThroughputSLI() *sli.TxnWriteThroughputSLI
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// GetStmtStats returns stmtstats.StatementStats owned by implementation.
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GetStmtStats() *stmtstats.StatementStats
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// ShowProcess returns ProcessInfo running in current Context
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ShowProcess() *util.ProcessInfo
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// GetAdvisoryLock acquires an advisory lock (aka GET_LOCK()).
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GetAdvisoryLock(string, int64) error
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// IsUsedAdvisoryLock checks for existing locks (aka IS_USED_LOCK()).
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IsUsedAdvisoryLock(string) uint64
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// ReleaseAdvisoryLock releases an advisory lock (aka RELEASE_LOCK()).
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ReleaseAdvisoryLock(string) bool
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// ReleaseAllAdvisoryLocks releases all advisory locks that this session holds.
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ReleaseAllAdvisoryLocks() int
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// GetExtensions returns the `*extension.SessionExtensions` object
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GetExtensions() *extension.SessionExtensions
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// InSandBoxMode indicates that this Session is in sandbox mode
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// Ref about sandbox mode: https://dev.mysql.com/doc/refman/8.0/en/expired-password-handling.html
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InSandBoxMode() bool
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// EnableSandBoxMode enable the sandbox mode of this Session
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EnableSandBoxMode()
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// DisableSandBoxMode enable the sandbox mode of this Session
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DisableSandBoxMode()
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// ReportUsageStats reports the usage stats to the global collector
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ReportUsageStats()
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// NewStmtIndexUsageCollector creates a new index usage collector for statement
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NewStmtIndexUsageCollector() *indexusage.StmtIndexUsageCollector
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}
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// TxnFuture is an interface where implementations have a kv.Transaction field and after
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// calling Wait of the TxnFuture, the kv.Transaction will become valid.
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type TxnFuture interface {
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// Wait converts pending txn to valid
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Wait(ctx context.Context, sctx Context) (kv.Transaction, error)
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}
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type basicCtxType int
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func (t basicCtxType) String() string {
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switch t {
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case QueryString:
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return "query_string"
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case Initing:
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return "initing"
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case LastExecuteDDL:
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return "last_execute_ddl"
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}
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return "unknown"
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}
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// Context keys.
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const (
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// QueryString is the key for original query string.
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QueryString basicCtxType = 1
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// Initing is the key for indicating if the server is running bootstrap or upgrade job.
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Initing basicCtxType = 2
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// LastExecuteDDL is the key for whether the session execute a ddl command last time.
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LastExecuteDDL basicCtxType = 3
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)
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// ValidateSnapshotReadTS strictly validates that readTS does not exceed the PD timestamp
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func ValidateSnapshotReadTS(ctx context.Context, sctx Context, readTS uint64) error {
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latestTS, err := sctx.GetStore().GetOracle().GetLowResolutionTimestamp(ctx, &oracle.Option{TxnScope: oracle.GlobalTxnScope})
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// If we fail to get latestTS or the readTS exceeds it, get a timestamp from PD to double check
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if err != nil || readTS > latestTS {
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metrics.ValidateReadTSFromPDCount.Inc()
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currentVer, err := sctx.GetStore().CurrentVersion(oracle.GlobalTxnScope)
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if err != nil {
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return errors.Errorf("fail to validate read timestamp: %v", err)
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}
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if readTS > currentVer.Ver {
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return errors.Errorf("cannot set read timestamp to a future time")
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}
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}
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return nil
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}
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// How far future from now ValidateStaleReadTS allows at most
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const allowedTimeFromNow = 100 * time.Millisecond
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// ValidateStaleReadTS validates that readTS does not exceed the current time not strictly.
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func ValidateStaleReadTS(ctx context.Context, sc *stmtctx.StatementContext, store kv.Storage, readTS uint64) error {
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currentTS, err := sc.GetStaleTSO()
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if currentTS == 0 || err != nil {
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currentTS, err = store.GetOracle().GetStaleTimestamp(ctx, oracle.GlobalTxnScope, 0)
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}
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// If we fail to calculate currentTS from local time, fallback to get a timestamp from PD
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if err != nil {
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metrics.ValidateReadTSFromPDCount.Inc()
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currentVer, err := store.CurrentVersion(oracle.GlobalTxnScope)
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if err != nil {
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return errors.Errorf("fail to validate read timestamp: %v", err)
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}
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currentTS = currentVer.Ver
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}
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if oracle.GetTimeFromTS(readTS).After(oracle.GetTimeFromTS(currentTS).Add(allowedTimeFromNow)) {
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return errors.Errorf("cannot set read timestamp to a future time")
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}
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return nil
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}
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