gitroast/vendor/github.com/pingcap/tidb/tidb.go

297 lines
8.5 KiB
Go

// Copyright 2013 The ql Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSES/QL-LICENSE file.
// Copyright 2015 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,
// See the License for the specific language governing permissions and
// limitations under the License.
package tidb
import (
"net/http"
"time"
// For pprof
_ "net/http/pprof"
"net/url"
"os"
"strings"
"sync"
"github.com/juju/errors"
"github.com/ngaut/log"
"github.com/pingcap/tidb/ast"
"github.com/pingcap/tidb/context"
"github.com/pingcap/tidb/domain"
"github.com/pingcap/tidb/executor"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/parser"
"github.com/pingcap/tidb/sessionctx/autocommit"
"github.com/pingcap/tidb/sessionctx/variable"
"github.com/pingcap/tidb/store/hbase"
"github.com/pingcap/tidb/store/localstore"
"github.com/pingcap/tidb/store/localstore/boltdb"
"github.com/pingcap/tidb/store/localstore/engine"
"github.com/pingcap/tidb/store/localstore/goleveldb"
"github.com/pingcap/tidb/util/types"
)
// Engine prefix name
const (
EngineGoLevelDBMemory = "memory://"
EngineGoLevelDBPersistent = "goleveldb://"
EngineBoltDB = "boltdb://"
EngineHBase = "hbase://"
defaultMaxRetries = 30
retrySleepInterval = 500 * time.Millisecond
)
type domainMap struct {
domains map[string]*domain.Domain
mu sync.Mutex
}
func (dm *domainMap) Get(store kv.Storage) (d *domain.Domain, err error) {
key := store.UUID()
dm.mu.Lock()
defer dm.mu.Unlock()
d = dm.domains[key]
if d != nil {
return
}
lease := time.Duration(0)
if !localstore.IsLocalStore(store) {
lease = schemaLease
}
d, err = domain.NewDomain(store, lease)
if err != nil {
return nil, errors.Trace(err)
}
dm.domains[key] = d
return
}
var (
domap = &domainMap{
domains: map[string]*domain.Domain{},
}
stores = make(map[string]kv.Driver)
// EnablePprof indicates whether to enable HTTP Pprof or not.
EnablePprof = os.Getenv("TIDB_PPROF") != "0"
// PprofAddr is the pprof url.
PprofAddr = "localhost:8888"
// store.UUID()-> IfBootstrapped
storeBootstrapped = make(map[string]bool)
// schemaLease is the time for re-updating remote schema.
// In online DDL, we must wait 2 * SchemaLease time to guarantee
// all servers get the neweset schema.
// Default schema lease time is 1 second, you can change it with a proper time,
// but you must know that too little may cause badly performance degradation.
// For production, you should set a big schema lease, like 300s+.
schemaLease = 1 * time.Second
)
// SetSchemaLease changes the default schema lease time for DDL.
// This function is very dangerous, don't use it if you really know what you do.
// SetSchemaLease only affects not local storage after bootstrapped.
func SetSchemaLease(lease time.Duration) {
schemaLease = lease
}
// What character set should the server translate a statement to after receiving it?
// For this, the server uses the character_set_connection and collation_connection system variables.
// It converts statements sent by the client from character_set_client to character_set_connection
// (except for string literals that have an introducer such as _latin1 or _utf8).
// collation_connection is important for comparisons of literal strings.
// For comparisons of strings with column values, collation_connection does not matter because columns
// have their own collation, which has a higher collation precedence.
// See: https://dev.mysql.com/doc/refman/5.7/en/charset-connection.html
func getCtxCharsetInfo(ctx context.Context) (string, string) {
sessionVars := variable.GetSessionVars(ctx)
charset := sessionVars.Systems["character_set_connection"]
collation := sessionVars.Systems["collation_connection"]
return charset, collation
}
// Parse parses a query string to raw ast.StmtNode.
func Parse(ctx context.Context, src string) ([]ast.StmtNode, error) {
log.Debug("compiling", src)
charset, collation := getCtxCharsetInfo(ctx)
stmts, err := parser.Parse(src, charset, collation)
if err != nil {
log.Warnf("compiling %s, error: %v", src, err)
return nil, errors.Trace(err)
}
return stmts, nil
}
// Compile is safe for concurrent use by multiple goroutines.
func Compile(ctx context.Context, rawStmt ast.StmtNode) (ast.Statement, error) {
compiler := &executor.Compiler{}
st, err := compiler.Compile(ctx, rawStmt)
if err != nil {
return nil, errors.Trace(err)
}
return st, nil
}
func runStmt(ctx context.Context, s ast.Statement, args ...interface{}) (ast.RecordSet, error) {
var err error
var rs ast.RecordSet
// before every execution, we must clear affectedrows.
variable.GetSessionVars(ctx).SetAffectedRows(0)
if s.IsDDL() {
err = ctx.FinishTxn(false)
if err != nil {
return nil, errors.Trace(err)
}
}
rs, err = s.Exec(ctx)
// All the history should be added here.
se := ctx.(*session)
se.history.add(0, s)
// MySQL DDL should be auto-commit
if s.IsDDL() || autocommit.ShouldAutocommit(ctx) {
if err != nil {
ctx.FinishTxn(true)
} else {
err = ctx.FinishTxn(false)
}
}
return rs, errors.Trace(err)
}
// GetRows gets all the rows from a RecordSet.
func GetRows(rs ast.RecordSet) ([][]types.Datum, error) {
if rs == nil {
return nil, nil
}
var rows [][]types.Datum
defer rs.Close()
// Negative limit means no limit.
for {
row, err := rs.Next()
if err != nil {
return nil, errors.Trace(err)
}
if row == nil {
break
}
rows = append(rows, row.Data)
}
return rows, nil
}
// RegisterStore registers a kv storage with unique name and its associated Driver.
func RegisterStore(name string, driver kv.Driver) error {
name = strings.ToLower(name)
if _, ok := stores[name]; ok {
return errors.Errorf("%s is already registered", name)
}
stores[name] = driver
return nil
}
// RegisterLocalStore registers a local kv storage with unique name and its associated engine Driver.
func RegisterLocalStore(name string, driver engine.Driver) error {
d := localstore.Driver{Driver: driver}
return RegisterStore(name, d)
}
// NewStore creates a kv Storage with path.
//
// The path must be a URL format 'engine://path?params' like the one for
// tidb.Open() but with the dbname cut off.
// Examples:
// goleveldb://relative/path
// boltdb:///absolute/path
// hbase://zk1,zk2,zk3/hbasetbl?tso=127.0.0.1:1234
//
// The engine should be registered before creating storage.
func NewStore(path string) (kv.Storage, error) {
return newStoreWithRetry(path, defaultMaxRetries)
}
func newStoreWithRetry(path string, maxRetries int) (kv.Storage, error) {
url, err := url.Parse(path)
if err != nil {
return nil, errors.Trace(err)
}
name := strings.ToLower(url.Scheme)
d, ok := stores[name]
if !ok {
return nil, errors.Errorf("invalid uri format, storage %s is not registered", name)
}
var s kv.Storage
for i := 1; i <= maxRetries; i++ {
s, err = d.Open(path)
if err == nil || !kv.IsRetryableError(err) {
break
}
sleepTime := time.Duration(uint64(retrySleepInterval) * uint64(i))
log.Warnf("Waiting store to get ready, sleep %v and try again...", sleepTime)
time.Sleep(sleepTime)
}
return s, errors.Trace(err)
}
var queryStmtTable = []string{"explain", "select", "show", "execute", "describe", "desc", "admin"}
func trimSQL(sql string) string {
// Trim space.
sql = strings.TrimSpace(sql)
// Trim leading /*comment*/
// There may be multiple comments
for strings.HasPrefix(sql, "/*") {
i := strings.Index(sql, "*/")
if i != -1 && i < len(sql)+1 {
sql = sql[i+2:]
sql = strings.TrimSpace(sql)
continue
}
break
}
// Trim leading '('. For `(select 1);` is also a query.
return strings.TrimLeft(sql, "( ")
}
// IsQuery checks if a sql statement is a query statement.
func IsQuery(sql string) bool {
sqlText := strings.ToLower(trimSQL(sql))
for _, key := range queryStmtTable {
if strings.HasPrefix(sqlText, key) {
return true
}
}
return false
}
func init() {
// Register default memory and goleveldb storage
RegisterLocalStore("memory", goleveldb.MemoryDriver{})
RegisterLocalStore("goleveldb", goleveldb.Driver{})
RegisterLocalStore("boltdb", boltdb.Driver{})
RegisterStore("hbase", hbasekv.Driver{})
// start pprof handlers
if EnablePprof {
go http.ListenAndServe(PprofAddr, nil)
}
}