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Type: Task
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Resolution: Done
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Affects Version/s: None
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Component/s: None
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It used to be possible to create a checkpoint on an empty table, that is no longer possible. The checkpoint call returns success, but creating a cursor fails. Creating a checkpoint on an empty table allows for simpler handling of checkpoint cursors.
The change in behavior was introduced in this commit:
https://github.com/wiredtiger/wiredtiger/commit/6de0cd586b32095952e4d739b0e5eeb5b84712e2
The following patch includes a test case that displays the behavior, and a fix to revert the behavior:
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diff --git a/src/txn/txn_ckpt.c b/src/txn/txn_ckpt.c index 3304011..7452aef 100644 --- a/src/txn/txn_ckpt.c +++ b/src/txn/txn_ckpt.c @@ -393,7 +393,7 @@ __wt_checkpoint(WT_SESSION_IMPL *session, const char *cfg[]) * ensure a checkpoint happens, but otherwise, the object isn't dirty * and the existing checkpoints are sufficient. */ - if (btree->modified == 0 && !force) + if (btree->modified == 0 && !force && btree->checkpoint != NULL) goto skip; /* Drop checkpoints with the same name as the one we're taking. */ diff --git a/test/suite/test_checkpoint02.py b/test/suite/test_checkpoint02.py new file mode 100644 index 0000000..7ce648e --- /dev/null +++ b/test/suite/test_checkpoint02.py @@ -0,0 +1,54 @@ +#!/usr/bin/env python +# +# Public Domain 2008-2012 WiredTiger, Inc. +# +# This is free and unencumbered software released into the public domain. +# +# Anyone is free to copy, modify, publish, use, compile, sell, or +# distribute this software, either in source code form or as a compiled +# binary, for any purpose, commercial or non-commercial, and by any +# means. +# +# In jurisdictions that recognize copyright laws, the author or authors +# of this software dedicate any and all copyright interest in the +# software to the public domain. We make this dedication for the benefit +# of the public at large and to the detriment of our heirs and +# successors. We intend this dedication to be an overt act of +# relinquishment in perpetuity of all present and future rights to this +# software under copyright law. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR +# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, +# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +# OTHER DEALINGS IN THE SOFTWARE. + +import wiredtiger, wttest +from helper import key_populate, simple_populate + +# test_checkpoint02.py +# Checkpoint of an empty table. + +class test_checkpoint(wttest.WiredTigerTestCase): + scenarios = [ + ('file', dict(uri='file:checkpoint',fmt='S')), + ('table', dict(uri='table:checkpoint',fmt='S')) + ] + + def test_checkpoint(self): + # Build a file with a set of checkpoints, and confirm they all have + # the correct key/value pairs. + self.session.create(self.uri, + "key_format=" + self.fmt + ",value_format=S") + + # Take a checkpoint on the empty table. + self.session.checkpoint() + + # Verify that the checkpoint is present. + cursor = self.session.open_cursor( + self.uri, None, "checkpoint=WiredTigerCheckpoint") + +if __name__ == '__main__': + wttest.run()
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- related to
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WT-302 Create checkpoints on empty tables.
- Closed