[PDS-119625] Log the Exception, not UnsafeArg.of(exceptionMessage) (#…

…4822)

* Log exception, not Unsafe message

* Add generated changelog entries

atlasdb-cassandra/src/main/java/com/palantir/atlasdb/keyvalue/cassandra/CassandraClientPoolingContainer.java

@@ -113,7 +113,7 @@ public <V, K extends Exception> V runWithPooledResource(FunctionCheckedException
             return runWithGoodResource(fn);
         } catch (Throwable t) {
             log.warn("Error occurred talking to host '{}': {}",
-                    SafeArg.of("host", CassandraLogHelper.host(host)), UnsafeArg.of("exception", t.toString()));
+                    SafeArg.of("host", CassandraLogHelper.host(host)), t);
             if (t instanceof NoSuchElementException && t.getMessage().contains("Pool exhausted")) {
                 log.warn("Extra information about exhausted pool",
                         SafeArg.of("numActive", clientPool.getNumActive()),

changelog/@unreleased/pr-4822.v2.yml

@@ -0,0 +1,8 @@
+type: fix
+fix:
+  description: The type and stack trace of Exceptions when talking to Cassandra are
+    now logged (and in the case of Safe exceptions, the exception message will also
+    be available). Previously, only the exception message was logged, and this was
+    always Unsafe.
+  links:
+  - https://github.com/palantir/atlasdb/pull/4822