Description
The WT_CURSOR.search_near method can return an incorrect key/value pair if the update record for an insert object is invisible to the session.
What happens is we successfully find the insert object and take the key from it; because the update record is invisible, we fall-through to the case where we're taking a value from the on-page cell, and we return the insert object's key with the last-known on-page object's value.
- This is a row-store test, but I expect the same failure happens for column-store as well.
- We can't simply switch to taking the on-page cell key/value pair, because there may be insert objects that are visible to the transaction.
Here's the script:
def test_insert_list_invisible(self):
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# Open a table an insert a bunch of records.
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uri = 'table:xxx'
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self.session.create(uri, 'key_format=S,value_format=S')
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cursor = self.session.open_cursor(uri, None)
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for i in range(1, 40):
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cursor.set_key(key_populate(cursor, i))
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cursor.set_value(value_populate(cursor, i))
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cursor.insert()
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cursor.close()
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# Close/reopen the table to move the records "on-page".
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self.reopen_conn()
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# Append more records, making them visible.
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cursor = self.session.open_cursor(uri, None)
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for i in range(40, 50):
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cursor.set_key(key_populate(cursor, i))
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cursor.set_value(value_populate(cursor, i))
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cursor.insert()
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# Append more records, making them invisible.
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self.session.begin_transaction()
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cursor = self.session.open_cursor(uri, None)
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for i in range(50, 60):
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cursor.set_key(key_populate(cursor, i))
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cursor.set_value(value_populate(cursor, i))
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cursor.insert()
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# Search-near in the middle of the invisible records.
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s = self.conn.open_session()
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cursor = s.open_cursor(uri, None)
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cursor.set_key(key_populate(cursor, 55))
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cursor.search_near()
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print cursor.get_key() + "/" + cursor.get_value()
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Attachments
Issue Links
- related to
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WT-1071 Invisible update changes.
- Closed