[Bug] Ignore drop table log when table has been dropped #5973
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morningman
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Jun 4, 2021
| Table table = db.getTable(tableId); | ||
| // delete from db meta | ||
| db.writeLock(); | ||
| if (table == null) { |
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move it before db.writeLock();
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morningman
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This was referenced Aug 5, 2021
EmmyMiao87
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Nov 10, 2021
Although the table lock can control the simultaneous modification of the table by different threads. But it cannot control the drop operation of the table by other threads. For example, when drop table and table update occur at the same time. get table object by thread 1 drop table by thread 2 with table lock update table object by thread 1 The above process is possible. At this time, step 3 actually operates a table that no longer exists, which will eventually cause NullPointerException. In fact, the modified table log after the drop table can be ignored. The reason is that it is meaningless to modify information on a table that no longer exists. Fixed apache#5687
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Proposed changes
Although the table lock can control the simultaneous modification of the table by different threads.
But it cannot control the drop operation of the table by other threads.
For example, when drop table and table update occur at the same time.
get table object by thread 1
drop table by thread 2 with table lock
update table object by thread 1
The above process is possible.
At this time, step 3 actually operates a table that no longer exists, which will eventually cause NullPointerException.
In fact, the modified table log after the drop table can be ignored. The reason is that it is meaningless to modify information on a table that no longer exists.
Fixed #5687
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