Add 'failure_ts' column to 'destinations' table (#6016)

Track the time that a server started failing at, for general analysis purposes.

2 files changed, 41 insertions, 7 deletions

diff --git a/synapse/storage/schema/delta/56/destinations_failure_ts.sql b/synapse/storage/schema/delta/56/destinations_failure_ts.sql
new file mode 100644
index 0000000000..f00889290b
--- /dev/null
+++ b/synapse/storage/schema/delta/56/destinations_failure_ts.sql
@@ -0,0 +1,25 @@
+/* Copyright 2019 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Record the timestamp when a given server started failing
+ */
+ALTER TABLE destinations ADD failure_ts BIGINT;
+
+/* as a rough approximation, we assume that the server started failing at
+ * retry_interval before the last retry
+ */
+UPDATE destinations SET failure_ts = retry_last_ts - retry_interval
+    WHERE retry_last_ts > 0;
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index d81ace0ece..289c117396 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -165,7 +165,7 @@ class TransactionStore(SQLBaseStore):
             txn,
             table="destinations",
             keyvalues={"destination": destination},
-            retcols=("destination", "retry_last_ts", "retry_interval"),
+            retcols=("destination", "failure_ts", "retry_last_ts", "retry_interval"),
             allow_none=True,
         )
 
@@ -174,12 +174,15 @@ class TransactionStore(SQLBaseStore):
         else:
             return None
 
-    def set_destination_retry_timings(self, destination, retry_last_ts, retry_interval):
+    def set_destination_retry_timings(
+        self, destination, failure_ts, retry_last_ts, retry_interval
+    ):
         """Sets the current retry timings for a given destination.
         Both timings should be zero if retrying is no longer occuring.
 
         Args:
             destination (str)
+            failure_ts (int|None) - when the server started failing (ms since epoch)
             retry_last_ts (int) - time of last retry attempt in unix epoch ms
             retry_interval (int) - how long until next retry in ms
         """
@@ -189,12 +192,13 @@ class TransactionStore(SQLBaseStore):
             "set_destination_retry_timings",
             self._set_destination_retry_timings,
             destination,
+            failure_ts,
             retry_last_ts,
             retry_interval,
         )
 
     def _set_destination_retry_timings(
-        self, txn, destination, retry_last_ts, retry_interval
+        self, txn, destination, failure_ts, retry_last_ts, retry_interval
     ):
 
         if self.database_engine.can_native_upsert:
@@ -202,9 +206,12 @@ class TransactionStore(SQLBaseStore):
             # resetting it) or greater than the existing retry interval.
 
             sql = """
-                INSERT INTO destinations (destination, retry_last_ts, retry_interval)
-                    VALUES (?, ?, ?)
+                INSERT INTO destinations (
+                    destination, failure_ts, retry_last_ts, retry_interval
+                )
+                    VALUES (?, ?, ?, ?)
                 ON CONFLICT (destination) DO UPDATE SET
+                        failure_ts = EXCLUDED.failure_ts,
                         retry_last_ts = EXCLUDED.retry_last_ts,
                         retry_interval = EXCLUDED.retry_interval
                     WHERE
@@ -212,7 +219,7 @@ class TransactionStore(SQLBaseStore):
                         OR destinations.retry_interval < EXCLUDED.retry_interval
             """
 
-            txn.execute(sql, (destination, retry_last_ts, retry_interval))
+            txn.execute(sql, (destination, failure_ts, retry_last_ts, retry_interval))
 
             return
 
@@ -225,7 +232,7 @@ class TransactionStore(SQLBaseStore):
             txn,
             table="destinations",
             keyvalues={"destination": destination},
-            retcols=("retry_last_ts", "retry_interval"),
+            retcols=("failure_ts", "retry_last_ts", "retry_interval"),
             allow_none=True,
         )
 
@@ -235,6 +242,7 @@ class TransactionStore(SQLBaseStore):
                 table="destinations",
                 values={
                     "destination": destination,
+                    "failure_ts": failure_ts,
                     "retry_last_ts": retry_last_ts,
                     "retry_interval": retry_interval,
                 },
@@ -245,6 +253,7 @@ class TransactionStore(SQLBaseStore):
                 "destinations",
                 keyvalues={"destination": destination},
                 updatevalues={
+                    "failure_ts": failure_ts,
                     "retry_last_ts": retry_last_ts,
                     "retry_interval": retry_interval,
                 },