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):
# Open a table an insert a bunch of records.
uri = 'table:xxx'
self.session.create(uri, 'key_format=S,value_format=S')
cursor = self.session.open_cursor(uri, None)
for i in range(1, 40):
cursor.set_key(key_populate(cursor, i))
cursor.set_value(value_populate(cursor, i))
cursor.insert()
cursor.close()
# Close/reopen the table to move the records "on-page".
self.reopen_conn()
# Append more records, making them visible.
cursor = self.session.open_cursor(uri, None)
for i in range(40, 50):
cursor.set_key(key_populate(cursor, i))
cursor.set_value(value_populate(cursor, i))
cursor.insert()
# Append more records, making them invisible.
self.session.begin_transaction()
cursor = self.session.open_cursor(uri, None)
for i in range(50, 60):
cursor.set_key(key_populate(cursor, i))
cursor.set_value(value_populate(cursor, i))
cursor.insert()
# Search-near in the middle of the invisible records.
s = self.conn.open_session()
cursor = s.open_cursor(uri, None)
cursor.set_key(key_populate(cursor, 55))
cursor.search_near()
print cursor.get_key() + "/" + cursor.get_value()
- related to
-
WT-1071 Invisible update changes.
- Closed