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MDEV-20515 multi-update tries to position updated table by null reference
Cause
Join tmp table inserts null row because of OUTER JOIN, that's
expected. Since `multi_update::prepare2()` converted
`Item_temptable_rowid` into `Item_field` (28dbdf3
)
`multi_update::send_data()` accesses join tmp record directly and
treats it as a normal row ignoring null status of ref field. NULL ref
field is then treated as normal in `multi_update::do_updates()` which
tries to position updated table by reference 0.
Note that reference 0 may be valid reference and the first row of
table can be wrongly updated (see multi_update.test).
Fix
Do not add row into multi-update tmp table in case of null ref
field. Join tmp table does not have null_row status at this time (as
well as `STATUS_NULL_ROW`) and cannot be skipped by these properties
(see first comment in multi_update::send_data()). But it has all null
fields (including the ref field).
This commit is contained in:
@ -1081,3 +1081,20 @@ b c
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2 0
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drop view v1;
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drop table t0, t1,t2;
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#
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# MDEV-20515 multi-update tries to position updated table by null reference
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#
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create or replace table t1 (a int);
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insert into t1 values (0), (2);
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create or replace table t2 (b int);
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insert into t2 values (1), (2);
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select * from t1 left join t2 on a = b order by b;
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a b
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0 NULL
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2 2
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update t1 left join t2 on a = b set b= 3 order by b;
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select * from t2;
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b
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1
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3
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drop tables t1, t2;
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