ddl: fix alter table share rowid bit problem

ddl/db_test.go

@@ -2671,3 +2671,40 @@ 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")
+	defer 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 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

@@ -1563,6 +1563,7 @@ func handleTableOptions(options []*ast.TableOption, tbInfo *model.TableInfo) err
 			if tbInfo.ShardRowIDBits > shardRowIDBitsMax {
 				tbInfo.ShardRowIDBits = shardRowIDBitsMax
 			}
+			tbInfo.MaxShardRowIDBits = tbInfo.ShardRowIDBits
 		}
 	}
 
@@ -1804,6 +1805,14 @@ 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 = verifyNoOverflowShardBits(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

@@ -27,7 +27,9 @@ 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"
@@ -469,7 +471,7 @@ 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 {
@@ -481,7 +483,22 @@ 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 = verifyNoOverflowShardBits(w.sessPool, tbl, shardRowIDBits)
+		if err != nil {
+			job.State = model.JobStateCancelled
+			return ver, err
+		}
+		tblInfo.ShardRowIDBits = shardRowIDBits
+		// MaxShardRowIDBits use to check the overflow of auto ID.
+		tblInfo.MaxShardRowIDBits = shardRowIDBits
+	}
 	ver, err = updateVersionAndTableInfo(t, job, tblInfo, true)
 	if err != nil {
 		job.State = model.JobStateCancelled
@@ -491,6 +508,25 @@ func onShardRowID(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 	return ver, nil
 }
 
+func verifyNoOverflowShardBits(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

@@ -51,7 +51,7 @@ require (
 	github.com/pingcap/goleveldb v0.0.0-20171020122428-b9ff6c35079e
 	github.com/pingcap/kvproto v0.0.0-20190215154024-7f2fc73ef562
 	github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596
-	github.com/pingcap/parser v0.0.0-20190404052804-c29af83ede25
+	github.com/pingcap/parser v0.0.0-20190404080625-e357a068a3e1
 	github.com/pingcap/pd v2.1.0-rc.4+incompatible
 	github.com/pingcap/tidb-tools v2.1.3-0.20190321065848-1e8b48f5c168+incompatible
 	github.com/pingcap/tipb v0.0.0-20190107072121-abbec73437b7

go.sum

@@ -119,8 +119,8 @@ github.com/pingcap/kvproto v0.0.0-20190215154024-7f2fc73ef562 h1:32oF1/8lVnBR2JV
 github.com/pingcap/kvproto v0.0.0-20190215154024-7f2fc73ef562/go.mod h1:QMdbTAXCHzzygQzqcG9uVUgU2fKeSN1GmfMiykdSzzY=
 github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596 h1:t2OQTpPJnrPDGlvA+3FwJptMTt6MEPdzK1Wt99oaefQ=
 github.com/pingcap/log v0.0.0-20190307075452-bd41d9273596/go.mod h1:WpHUKhNZ18v116SvGrmjkA9CBhYmuUTKL+p8JC9ANEw=
-github.com/pingcap/parser v0.0.0-20190404052804-c29af83ede25 h1:K7DB0kOkSETe3/4rpbzF/Iv4IgfkGBNu5EfaXxaiBuc=
-github.com/pingcap/parser v0.0.0-20190404052804-c29af83ede25/go.mod h1:1FNvfp9+J0wvc4kl8eGNh7Rqrxveg15jJoWo/a0uHwA=
+github.com/pingcap/parser v0.0.0-20190404080625-e357a068a3e1 h1:TOaneg32HXTvr6Gk2Dd1EwtLE6L1nbUNVasLxt6ZrVA=
+github.com/pingcap/parser v0.0.0-20190404080625-e357a068a3e1/go.mod h1:1FNvfp9+J0wvc4kl8eGNh7Rqrxveg15jJoWo/a0uHwA=
 github.com/pingcap/pd v2.1.0-rc.4+incompatible h1:/buwGk04aHO5odk/+O8ZOXGs4qkUjYTJ2UpCJXna8NE=
 github.com/pingcap/pd v2.1.0-rc.4+incompatible/go.mod h1:nD3+EoYes4+aNNODO99ES59V83MZSI+dFbhyr667a0E=
 github.com/pingcap/tidb-tools v2.1.3-0.20190321065848-1e8b48f5c168+incompatible h1:MkWCxgZpJBgY2f4HtwWMMFzSBb3+JPzeJgF3VrXE/bU=

table/tables/tables.go

@@ -925,7 +925,8 @@ func (t *tableCommon) AllocAutoID(ctx sessionctx.Context) (int64, error) {
 		return 0, 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
@@ -945,9 +946,9 @@ 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 checks 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
 }