Import wiredtiger: 3b4a927265fc81dc4ab8895c5451a7ec9582c1d3 from branch mongodb-4.4

ref: 3998a1f701..3b4a927265
for: 4.4.0-rc11

WT-6349       Don't clean the globally visible on-disk tombstones as part of checkpoint
WT-6351       Fix race between threads to update condition variable's previous wait value
WT-6388       Fix-up out-of-order updates in the history store
WT-6397       Reduce visibility restrictions for reading tombstone information from history store's update list
WT-6428       Fixes for checkpoint retention
WT-6429       Fix memory leak in rollback to stable
WT-6438       Fix rollback error due to cache pressure
WT-6441       Add stats to indicate how many times the history store is search happened during a normal search call

1 files changed, 88 insertions, 0 deletions

diff --git a/src/third_party/wiredtiger/test/suite/test_timestamp20.py b/src/third_party/wiredtiger/test/suite/test_timestamp20.py
new file mode 100644
index 00000000000..69aec301a47
--- /dev/null
+++ b/src/third_party/wiredtiger/test/suite/test_timestamp20.py
@@ -0,0 +1,88 @@
+#!/usr/bin/env python
+#
+# Public Domain 2014-2020 MongoDB, Inc.
+# Public Domain 2008-2014 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
+
+def timestamp_str(t):
+    return '%x' % t
+
+# test_timestamp20.py
+# Exercise fixing up of out-of-order updates in the history store.
+class test_timestamp20(wttest.WiredTigerTestCase):
+    conn_config = 'cache_size=50MB'
+    session_config = 'isolation=snapshot'
+
+    def test_timestamp20(self):
+        uri = 'table:test_timestamp20'
+        self.session.create(uri, 'key_format=S,value_format=S')
+        self.conn.set_timestamp('oldest_timestamp=' + timestamp_str(1))
+        cursor = self.session.open_cursor(uri)
+
+        value1 = 'a' * 500
+        value2 = 'b' * 500
+        value3 = 'c' * 500
+        value4 = 'd' * 500
+        value5 = 'e' * 500
+
+        for i in range(1, 10000):
+            self.session.begin_transaction()
+            cursor[str(i)] = value1
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(10))
+
+        for i in range(1, 10000):
+            self.session.begin_transaction()
+            cursor[str(i)] = value2
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(20))
+
+        for i in range(1, 10000):
+            self.session.begin_transaction()
+            cursor[str(i)] = value3
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(30))
+
+        old_reader_session = self.conn.open_session()
+        old_reader_cursor = old_reader_session.open_cursor(uri)
+        old_reader_session.begin_transaction('read_timestamp=' + timestamp_str(30))
+
+        # Now put two updates out of order. 5 will go to the history store and will trigger a
+        # correction to the existing contents.
+        for i in range(1, 10000):
+            self.session.begin_transaction()
+            cursor[str(i)] = value4
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(5))
+            self.session.begin_transaction()
+            cursor[str(i)] = value5
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(40))
+
+        self.session.begin_transaction('read_timestamp=' + timestamp_str(30))
+        for i in range(1, 10000):
+            self.assertEqual(cursor[str(i)], value4)
+        self.session.rollback_transaction()
+
+        for i in range(1, 10000):
+            self.assertEqual(old_reader_cursor[str(i)], value3)
+        old_reader_session.rollback_transaction()