WT-8151 Make durable_start_ts equal to stop_ts if stop_ts is less tha…

…n durable_start_ts and greater than start_ts (#7086)

src/reconcile/rec_visibility.c

@@ -255,6 +255,20 @@ __timestamp_out_of_order_fix(WT_SESSION_IMPL *session, WT_TIME_WINDOW *select_tw
         select_tw->start_ts = select_tw->stop_ts;
         return (true);
     }
+
+    /*
+     * As per the time window validation the durable_start_ts must not be greater than the stop_ts.
+     * Hence, if the stop_ts is less than durable_start_ts and greater than start_ts, make
+     * durable_start_ts equal to stop_ts.
+     */
+    if ((select_tw->start_ts != select_tw->stop_ts) &&
+      (select_tw->stop_ts < select_tw->durable_start_ts)) {
+        __wt_verbose(session, WT_VERB_TIMESTAMP,
+          "Warning: fixing out-of-order timestamps remove earlier than value; time window %s",
+          __wt_time_window_to_string(select_tw, time_string));
+
+        select_tw->durable_start_ts = select_tw->stop_ts;
+    }
     return (false);
 }
 

test/suite/test_prepare17.py

@@ -0,0 +1,122 @@
+#!/usr/bin/env python
+#
+# Public Domain 2014-present 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
+from wtscenario import make_scenarios
+from helper import simulate_crash_restart
+
+# test_prepare17.py
+# The following test is to verify that if the out of order commit timestamp(for a transaction, say T2) lies between
+# previous commit and durable timestamps(for a transaction, say T1), the durable timestamp of T1 changes to
+# the commit timestamp of T2.
+class test_prepare17(wttest.WiredTigerTestCase):
+    session_config = 'isolation=snapshot'
+    uri = 'table:test_prepare17'
+    nrows = 1000
+    value1 = 'aaaaa'
+    value2 = 'bbbbb'
+
+    key_format_values = [
+        ('integer-row', dict(key_format='i')),
+        ('column', dict(key_format='r')),
+    ]
+    update = [
+        ('prepare', dict(prepare=True)),
+        ('non-prepare', dict(prepare=False)),
+    ]
+    scenarios = make_scenarios(key_format_values, update)
+
+    def test_prepare(self):
+        create_params = 'key_format={},value_format=S'.format(self.key_format)
+        self.session.create(self.uri, create_params)
+        cursor = self.session.open_cursor(self.uri)
+
+        # Transaction one
+        self.session.begin_transaction()
+        for i in range(1, self.nrows + 1):
+            cursor[i] = self.value1
+        self.session.prepare_transaction('prepare_timestamp=' + self.timestamp_str(2))
+        self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(3)+ ',durable_timestamp=' + self.timestamp_str(6))
+
+        # In the case below, the commit timestamp lies between the previous commit and durable timestamps.
+        # Internally, WiredTiger changes the durable timestamp of Transaction one, i.e. 6 to the commit timestamp 
+        # of the transaction below, i.e, 4.
+        # As per the time window validation the commit timestamp cannot be in between any previous commit and 
+        # durable timestamps.
+        #
+        # Note: The scenario where commit timestamp lies between the previous commit and durable timestamps
+        # is not expected from MongoDB, but WiredTiger API can allow it.
+        if self.prepare:
+            self.session.begin_transaction()
+            for i in range(1, self.nrows + 1):
+                cursor[i] = self.value2
+            self.session.prepare_transaction('prepare_timestamp=' + self.timestamp_str(3))
+            self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(4) + ',durable_timestamp=' + self.timestamp_str(7))
+        else:
+            self.session.begin_transaction()
+            for i in range(1, self.nrows + 1):
+                cursor[i] = self.value2
+            self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(4))
+
+        # Time window validation occurs as part of checkpoint.
+        self.session.checkpoint()
+
+    def test_prepare_insert_remove(self):
+        if not self.prepare:
+            return
+
+        create_params = 'key_format={},value_format=S'.format(self.key_format)
+        self.session.create(self.uri, create_params)
+        cursor = self.session.open_cursor(self.uri)
+
+        self.session.begin_transaction()
+        for i in range(1, self.nrows + 1):
+            cursor[i] = self.value1
+        self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(2))
+
+        # Transaction 2
+        self.session.begin_transaction()
+        for i in range(1, self.nrows + 1):
+            cursor[i] = self.value2
+            cursor.set_key(i)
+            cursor.remove()
+        self.session.prepare_transaction('prepare_timestamp=' + self.timestamp_str(3))
+        self.session.commit_transaction('commit_timestamp=' + self.timestamp_str(4) + ',durable_timestamp=' + self.timestamp_str(7))
+
+        self.conn.set_timestamp('stable_timestamp=' + self.timestamp_str(6))
+        self.session.checkpoint()
+        simulate_crash_restart(self, ".", "RESTART")
+
+        # Update in Transaction2 should be removed as the stable timestamp (6) is less than the durable timestamp (7).
+        cursor = self.session.open_cursor(self.uri)
+        self.session.begin_transaction()
+        for i in range(1, self.nrows + 1):
+            cursor.set_key(i)
+            cursor.search()
+            self.assertEqual(cursor.get_value(), self.value1)
+        self.session.rollback_transaction()