ddl: fix alter table share rowid bit problem

ddl/db_test.go

@@ -2672,3 +2672,39 @@ func (s *testDBSuite) TestModifyColumnCharset(c *C) {
 			") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
 
 }
+
+func (s *testDBSuite) TestAlterShardRowIDBits(c *C) {
+	s.tk = testkit.NewTestKit(c, s.store)
+	tk := s.tk
+
+	tk.MustExec("use test")
+	// Test alter shard_row_id_bits
+	tk.MustExec("drop table if exists t1")
+	tk.MustExec("create table t1 (a int) shard_row_id_bits = 5")
+	tk.MustExec(fmt.Sprintf("alter table t1 auto_increment = %d;", 1<<56))
+	tk.MustExec("insert into t1 set a=1;")
+
+	// Test increase shard_row_id_bits failed by overflow global auto ID.
+	_, err := tk.Exec(" alter table t1 SHARD_ROW_ID_BITS = 10;")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[autoid:1467]shard_row_id_bits 10 will cause next global auto ID will overflow")
+
+	// Test reduce shard_row_id_bits will be ok.
+	tk.MustExec(" alter table t1 SHARD_ROW_ID_BITS = 3;")
+	checkShardRowID := func(maxShardRowIDBits, shardRowIDBits uint64) {
+		tbl := testGetTableByName(c, tk.Se, "test", "t1")
+		c.Assert(tbl.Meta().MaxShardRowIDBits == maxShardRowIDBits, IsTrue)
+		c.Assert(tbl.Meta().ShardRowIDBits == shardRowIDBits, IsTrue)
+	}
+	checkShardRowID(5, 3)
+
+	// Test reduce shard_row_id_bits but calculate overflow should use the max record shard_row_id_bits.
+	tk.MustExec("drop table if exists t1")
+	tk.MustExec("create table t1 (a int) shard_row_id_bits = 10")
+	tk.MustExec(" alter table t1 SHARD_ROW_ID_BITS = 5;")
+	checkShardRowID(10, 5)
+	tk.MustExec(fmt.Sprintf("alter table t1 auto_increment = %d;", 1<<56))
+	_, err = tk.Exec("insert into t1 set a=1;")
+	c.Assert(err, NotNil)
+	c.Assert(err.Error(), Equals, "[autoid:1467]Failed to read auto-increment value from storage engine")
+}

ddl/ddl_api.go

@@ -1550,6 +1550,7 @@ func handleTableOptions(options []*ast.TableOption, tbInfo *model.TableInfo) err
 			if tbInfo.ShardRowIDBits > shardRowIDBitsMax {
 				tbInfo.ShardRowIDBits = shardRowIDBitsMax
 			}
+			tbInfo.MaxShardRowIDBits = tbInfo.ShardRowIDBits
 		}
 	}
 
@@ -1774,6 +1775,14 @@ func (d *ddl) ShardRowID(ctx sessionctx.Context, tableIdent ast.Ident, uVal uint
 	if ok && uVal != 0 {
 		return errUnsupportedShardRowIDBits
 	}
+	if uVal == t.Meta().ShardRowIDBits {
+		// Nothing need to do.
+		return nil
+	}
+	err = checkGlobalAutoID(d.sessPool, t, uVal)
+	if err != nil {
+		return err
+	}
 	job := &model.Job{
 		Type:       model.ActionShardRowID,
 		SchemaID:   schema.ID,

ddl/ddl_worker.go

@@ -525,7 +525,7 @@ func (w *worker) runDDLJob(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64,
 	case model.ActionRenameTable:
 		ver, err = onRenameTable(t, job)
 	case model.ActionShardRowID:
-		ver, err = onShardRowID(t, job)
+		ver, err = w.onShardRowID(d, t, job)
 	case model.ActionModifyTableComment:
 		ver, err = onModifyTableComment(t, job)
 	case model.ActionAddTablePartition:

ddl/table.go

@@ -26,7 +26,9 @@ import (
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/meta/autoid"
+	"github.com/pingcap/tidb/sessionctx"
 	"github.com/pingcap/tidb/table"
+	"github.com/pingcap/tidb/table/tables"
 	"github.com/pingcap/tidb/tablecodec"
 	"github.com/pingcap/tidb/util/gcutil"
 	"github.com/pingcap/tidb/util/logutil"
@@ -468,7 +470,7 @@ func onRebaseAutoID(store kv.Storage, t *meta.Meta, job *model.Job) (ver int64,
 	return ver, nil
 }
 
-func onShardRowID(t *meta.Meta, job *model.Job) (ver int64, _ error) {
+func (w *worker) onShardRowID(d *ddlCtx, t *meta.Meta, job *model.Job) (ver int64, _ error) {
 	var shardRowIDBits uint64
 	err := job.DecodeArgs(&shardRowIDBits)
 	if err != nil {
@@ -480,7 +482,21 @@ func onShardRowID(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 		job.State = model.JobStateCancelled
 		return ver, errors.Trace(err)
 	}
-	tblInfo.ShardRowIDBits = shardRowIDBits
+	if shardRowIDBits < tblInfo.ShardRowIDBits {
+		tblInfo.ShardRowIDBits = shardRowIDBits
+	} else {
+		tbl, err := getTable(d.store, job.SchemaID, tblInfo)
+		if err != nil {
+			return ver, errors.Trace(err)
+		}
+		err = checkGlobalAutoID(w.sessPool, tbl, shardRowIDBits)
+		if err != nil {
+			job.State = model.JobStateCancelled
+			return ver, err
+		}
+		tblInfo.ShardRowIDBits = shardRowIDBits
+		tblInfo.MaxShardRowIDBits = shardRowIDBits
+	}
 	ver, err = updateVersionAndTableInfo(t, job, tblInfo, true)
 	if err != nil {
 		job.State = model.JobStateCancelled
@@ -490,6 +506,25 @@ func onShardRowID(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 	return ver, nil
 }
 
+func checkGlobalAutoID(s *sessionPool, tbl table.Table, shardRowIDBits uint64) error {
+	var ctx sessionctx.Context
+	ctx, err := s.get()
+	if err != nil {
+		return errors.Trace(err)
+	}
+	defer s.put(ctx)
+
+	// Check next global max auto ID first.
+	autoIncID, err := tbl.Allocator(ctx).NextGlobalAutoID(tbl.Meta().ID)
+	if err != nil {
+		return errors.Trace(err)
+	}
+	if tables.OverflowShardBits(autoIncID, shardRowIDBits) {
+		return autoid.ErrAutoincReadFailed.GenWithStack("shard_row_id_bits %d will cause next global auto ID overflow", shardRowIDBits)
+	}
+	return nil
+}
+
 func onRenameTable(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 	var oldSchemaID int64
 	var tableName model.CIStr

go.mod

@@ -91,3 +91,5 @@ require (
 	sourcegraph.com/sourcegraph/appdash v0.0.0-20180531100431-4c381bd170b4
 	sourcegraph.com/sourcegraph/appdash-data v0.0.0-20151005221446-73f23eafcf67
 )
+
+replace github.com/pingcap/parser => github.com/crazycs520/parser v0.0.0-20190321024858-9d09878eb099

go.sum

@@ -23,6 +23,8 @@ github.com/coreos/go-systemd v0.0.0-20181031085051-9002847aa142 h1:3jFq2xL4ZajGK
 github.com/coreos/go-systemd v0.0.0-20181031085051-9002847aa142/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f h1:lBNOc5arjvs8E5mO2tbpBpLoyyu8B6e44T7hJy6potg=
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
+github.com/crazycs520/parser v0.0.0-20190321024858-9d09878eb099 h1:tElKJwuG/rdoGYtHtzi7oQwlmkoxk/15OZm46W9xbfY=
+github.com/crazycs520/parser v0.0.0-20190321024858-9d09878eb099/go.mod h1:xLjI+gnWYexq011WPMEvCNS8rFM9qe1vdojIEzSKPuc=
 github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548 h1:iwZdTE0PVqJCos1vaoKsclOGD3ADKpshg3SRtYBbwso=
 github.com/cznic/mathutil v0.0.0-20181122101859-297441e03548/go.mod h1:e6NPNENfs9mPDVNRekM7lKScauxd5kXTr1Mfyig6TDM=
 github.com/cznic/sortutil v0.0.0-20150617083342-4c7342852e65 h1:hxuZop6tSoOi0sxFzoGGYdRqNrPubyaIf9KoBG9tPiE=

table/tables/tables.go

@@ -928,7 +928,8 @@ func (t *tableCommon) AllocAutoID(ctx sessionctx.Context) (int64, error) {
 		return 0, errors.Trace(err)
 	}
 	if t.meta.ShardRowIDBits > 0 {
-		if t.overflowShardBits(rowID) {
+		// use max record ShardRowIDBits to check  overflow.
+		if OverflowShardBits(rowID, t.meta.MaxShardRowIDBits) {
 			// If overflow, the rowID may be duplicated. For examples,
 			// t.meta.ShardRowIDBits = 4
 			// rowID = 0010111111111111111111111111111111111111111111111111111111111111
@@ -948,9 +949,9 @@ func (t *tableCommon) AllocAutoID(ctx sessionctx.Context) (int64, error) {
 	return rowID, nil
 }
 
-// overflowShardBits check whether the rowID overflow `1<<(64-t.meta.ShardRowIDBits-1) -1`.
-func (t *tableCommon) overflowShardBits(rowID int64) bool {
-	mask := (1<<t.meta.ShardRowIDBits - 1) << (64 - t.meta.ShardRowIDBits - 1)
+// OverflowShardBits check whether the rowID overflow `1<<(64-shardRowIDBits-1) -1`.
+func OverflowShardBits(rowID int64, shardRowIDBits uint64) bool {
+	mask := (1<<shardRowIDBits - 1) << (64 - shardRowIDBits - 1)
 	return rowID&int64(mask) > 0
 }