sessionctx

Documentation

Index

• Constants
• func ValidateSnapshotReadTS(ctx context.Context, store kv.Storage, readTS uint64) error
• type Context
• type InstancePlanCache
• type SessionPlanCache
• type SessionStatesHandler
• type TxnFuture

Constants

const (
	// QueryString is the key for original query string.
	QueryString basicCtxType = 1
	// Initing is the key for indicating if the server is running bootstrap or upgrade job.
	Initing basicCtxType = 2
	// LastExecuteDDL is the key for whether the session execute a ddl command last time.
	LastExecuteDDL basicCtxType = 3
)

Context keys.

Functions

func ValidateSnapshotReadTS

func ValidateSnapshotReadTS(ctx context.Context, store kv.Storage, readTS uint64) error

ValidateSnapshotReadTS strictly validates that readTS does not exceed the PD timestamp

Types

type Context

type Context interface {
	SessionStatesHandler
	contextutil.ValueStoreContext
	tablelock.TableLockContext
	// RollbackTxn rolls back the current transaction.
	RollbackTxn(ctx context.Context)
	// CommitTxn commits the current transaction.
	// buffered KV changes will be discarded, call StmtCommit if you want to commit them.
	CommitTxn(ctx context.Context) error
	// Txn returns the current transaction which is created before executing a statement.
	// The returned kv.Transaction is not nil, but it maybe pending or invalid.
	// If the active parameter is true, call this function will wait for the pending txn
	// to become valid.
	Txn(active bool) (kv.Transaction, error)

	// GetClient gets a kv.Client.
	GetClient() kv.Client

	// GetMPPClient gets a kv.MPPClient.
	GetMPPClient() kv.MPPClient

	// Deprecated: the semantics of session.GetInfoSchema() is ambiguous
	// If you want to get the infoschema of the current transaction in SQL layer, use sessiontxn.GetTxnManager(ctx).GetTxnInfoSchema()
	// If you want to get the latest infoschema use `GetDomainInfoSchema`
	GetInfoSchema() infoschema.MetaOnlyInfoSchema

	// GetDomainInfoSchema returns the latest information schema in domain
	// Different with `domain.InfoSchema()`, the information schema returned by this method
	// includes the temporary table definitions stored in session
	GetDomainInfoSchema() infoschema.MetaOnlyInfoSchema

	GetSessionVars() *variable.SessionVars

	// GetSQLExecutor returns the sqlexec.SQLExecutor.
	GetSQLExecutor() sqlexec.SQLExecutor

	// GetRestrictedSQLExecutor returns the sqlexec.RestrictedSQLExecutor.
	GetRestrictedSQLExecutor() sqlexec.RestrictedSQLExecutor

	// GetExprCtx returns the expression context of the session.
	GetExprCtx() exprctx.ExprContext

	// GetTableCtx returns the table.MutateContext
	GetTableCtx() tblctx.MutateContext

	// GetPlanCtx gets the plan context of the current session.
	GetPlanCtx() planctx.PlanContext

	// GetDistSQLCtx gets the distsql ctx of the current session
	GetDistSQLCtx() *distsqlctx.DistSQLContext

	// GetRangerCtx returns the context used in `ranger` related functions
	GetRangerCtx() *rangerctx.RangerContext

	// GetBuildPBCtx gets the ctx used in `ToPB` of the current session
	GetBuildPBCtx() *planctx.BuildPBContext

	GetSessionManager() util.SessionManager

	// RefreshTxnCtx commits old transaction without retry,
	// and creates a new transaction.
	// now just for load data and batch insert.
	RefreshTxnCtx(context.Context) error

	// GetStore returns the store of session.
	GetStore() kv.Storage

	// GetSessionPlanCache returns the session-level cache of the physical plan.
	GetSessionPlanCache() SessionPlanCache

	// UpdateColStatsUsage updates the column stats usage.
	UpdateColStatsUsage(predicateColumns iter.Seq[model.TableItemID])

	// HasDirtyContent checks whether there's dirty update on the given table.
	HasDirtyContent(tid int64) bool

	// StmtCommit flush all changes by the statement to the underlying transaction.
	// it must be called before CommitTxn, else all changes since last StmtCommit
	// will be lost. For SQL statement, StmtCommit or StmtRollback is called automatically.
	// the "Stmt" not only means SQL statement, but also any KV changes, such as
	// meta KV.
	StmtCommit(ctx context.Context)
	// StmtRollback provides statement level rollback. The parameter `forPessimisticRetry` should be true iff it's used
	// for auto-retrying execution of DMLs in pessimistic transactions.
	// if error happens when you are handling batch of KV changes since last StmtCommit
	// or StmtRollback, and you don't want them to be committed, you must call StmtRollback
	// before you start another batch, otherwise, the previous changes might be committed
	// unexpectedly.
	StmtRollback(ctx context.Context, isForPessimisticRetry bool)
	// IsDDLOwner checks whether this session is DDL owner.
	IsDDLOwner() bool
	// PrepareTSFuture uses to prepare timestamp by future.
	PrepareTSFuture(ctx context.Context, future oracle.Future, scope string) error
	// GetPreparedTxnFuture returns the TxnFuture if it is valid or pending.
	// It returns nil otherwise.
	GetPreparedTxnFuture() TxnFuture
	// GetTxnWriteThroughputSLI returns the TxnWriteThroughputSLI.
	GetTxnWriteThroughputSLI() *sli.TxnWriteThroughputSLI
	// GetStmtStats returns stmtstats.StatementStats owned by implementation.
	GetStmtStats() *stmtstats.StatementStats
	// ShowProcess returns ProcessInfo running in current Context
	ShowProcess() *util.ProcessInfo
	// GetAdvisoryLock acquires an advisory lock (aka GET_LOCK()).
	GetAdvisoryLock(string, int64) error
	// IsUsedAdvisoryLock checks for existing locks (aka IS_USED_LOCK()).
	IsUsedAdvisoryLock(string) uint64
	// ReleaseAdvisoryLock releases an advisory lock (aka RELEASE_LOCK()).
	ReleaseAdvisoryLock(string) bool
	// ReleaseAllAdvisoryLocks releases all advisory locks that this session holds.
	ReleaseAllAdvisoryLocks() int
	// GetExtensions returns the `*extension.SessionExtensions` object
	GetExtensions() *extension.SessionExtensions
	// InSandBoxMode indicates that this Session is in sandbox mode
	// Ref about sandbox mode: https://dev.mysql.com/doc/refman/8.0/en/expired-password-handling.html
	InSandBoxMode() bool
	// EnableSandBoxMode enable the sandbox mode of this Session
	EnableSandBoxMode()
	// DisableSandBoxMode enable the sandbox mode of this Session
	DisableSandBoxMode()
	// ReportUsageStats reports the usage stats to the global collector
	ReportUsageStats()
	// NewStmtIndexUsageCollector creates a new index usage collector for statement
	NewStmtIndexUsageCollector() *indexusage.StmtIndexUsageCollector
	// GetCursorTracker returns the cursor tracker of the session
	GetCursorTracker() cursor.Tracker
	// GetCommitWaitGroup returns the wait group for async commit and secondary lock cleanup background goroutines
	GetCommitWaitGroup() *sync.WaitGroup
}

Context is an interface for transaction and executive args environment.

type InstancePlanCache

type InstancePlanCache interface {
	// Get gets the cached value from the cache according to key and opts.
	Get(key string, paramTypes any) (value any, ok bool)
	// Put puts the key and value into the cache.
	Put(key string, value, paramTypes any) (succ bool)
	// Evict evicts some cached values.
	Evict() (detailInfo string, numEvicted int)
	// Size returns the number of cached values.
	Size() int64
	// MemUsage returns the total memory usage of this plan cache.
	MemUsage() int64
	// GetLimits returns the soft and hard memory limits of this plan cache.
	GetLimits() (softLimit, hardLimit int64)
	// SetLimits sets the soft and hard memory limits of this plan cache.
	SetLimits(softLimit, hardLimit int64)
}

InstancePlanCache represents the instance/node level plan cache. Value and Opts should always be *PlanCacheValue and *PlanCacheMatchOpts, use any to avoid cycle-import.

type SessionPlanCache

type SessionPlanCache interface {
	Get(key string, paramTypes any) (value any, ok bool)
	Put(key string, value, paramTypes any)
	Delete(key string)
	DeleteAll()
	Size() int
	SetCapacity(capacity uint) error
	Close()
}

SessionPlanCache is an interface for prepare and non-prepared plan cache

type SessionStatesHandler

type SessionStatesHandler interface {
	// EncodeSessionStates encodes session states into a JSON.
	EncodeSessionStates(context.Context, Context, *sessionstates.SessionStates) error
	// DecodeSessionStates decodes a map into session states.
	DecodeSessionStates(context.Context, Context, *sessionstates.SessionStates) error
}

SessionStatesHandler is an interface for encoding and decoding session states.

type TxnFuture

type TxnFuture interface {
	// Wait converts pending txn to valid
	Wait(ctx context.Context, sctx Context) (kv.Transaction, error)
}

TxnFuture is an interface where implementations have a kv.Transaction field and after calling Wait of the TxnFuture, the kv.Transaction will become valid.