ddl: add data structure SubJob for multi-schema change
#35231
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| @@ -1456,9 +1456,6 @@ func GetColDefaultValue(ctx sessionctx.Context, col *table.Column, defaultVals [ | |||
| if col.GetOriginDefaultValue() == nil && mysql.HasNotNullFlag(col.GetFlag()) { | |||
| return colVal, errors.New("Miss column") | |||
| } | |||
| if col.State != model.StatePublic { | |||
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Consider the case:
create table t (a tinyint);
insert into t set a = 10 ;
alter table t add column b int not null, change column a c char(5) first;In this ALTER TABLE statement, we add a NOT NULL column first, and then do the lossy column type change. In the phase of backfilling, the schema state of column b is still "write-reorg". If we keep this code, a null value is assigned to the column b, which violates the not-null constraint. Also see tangenta#94.
I don't see if there are any benefits to get a null value for the middle-state column... so let it be the real default value.
No tests are broken by this change.
No other tests except TestColumnAdd are broken by this change.
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Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/6a94b8a4dc79debfe7f681e9781f9ca08b9cefee |
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This pull request has been accepted and is ready to merge. Commit hash: 6a94b8a
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TiDB MergeCI notify🔴 Bad News! New failing [1] after this pr merged.
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What problem does this PR solve?
Issue Number: ref #14766
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What is changed and how it works?
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