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when altering a table with one new column, pb8 was hanged and i close and reopen and again the same problem is coming, does any body know to solve this issue...

asked 25 Mar '13, 07:07

kvraman03's gravatar image

kvraman03
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accept rate: 0%

edited 25 Mar '13, 07:44

Volker%20Barth's gravatar image

Volker Barth
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ALTER TABLE ... ADD COLUMN requires an exclusive lock: all other transactions that are referencing the table must commit before the ALTER can proceed.

Also, in v7 the ALTER must rewrite all of the rows. If the table is large, it can take a significant amount of time. The exclusive lock is held the entire time so while the ALTER is in progress, all other connections that attempt to access the table will block.

-john.

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answered 25 Mar '13, 07:12

John%20Smirnios's gravatar image

John Smirnios
10.7k392141
accept rate: 38%

Thank you john, it worked..

(25 Mar '13, 07:38) kvraman03
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question asked: 25 Mar '13, 07:07

question was seen: 1,540 times

last updated: 25 Mar '13, 07:44