CPP-884 Deprecate pending request timeouts metric

Also, remove unused internal logic and test

Author: Michael Penick

include/cassandra.h

@@ -423,7 +423,7 @@ typedef struct CassMetrics_ {
 
   struct {
     cass_uint64_t connection_timeouts; /**< Occurrences of a connection timeout */
-    cass_uint64_t pending_request_timeouts; /**< Occurrences of requests that timed out waiting for a connection */
+    cass_uint64_t pending_request_timeouts; /**< Deprecated */
     cass_uint64_t request_timeouts; /**< Occurrences of requests that timed out waiting for a request to finish */
   } errors; /**< Error metrics */
 } CassMetrics;

src/metrics.hpp

@@ -420,7 +420,6 @@ class Metrics : public Allocated {
       , request_rates(&thread_state_)
       , total_connections(&thread_state_)
       , connection_timeouts(&thread_state_)
-      , pending_request_timeouts(&thread_state_)
       , request_timeouts(&thread_state_) {}
 
   void record_request(uint64_t latency_ns) {
@@ -446,7 +445,6 @@ class Metrics : public Allocated {
   Counter total_connections;
 
   Counter connection_timeouts;
-  Counter pending_request_timeouts;
   Counter request_timeouts;
 
 private:

src/session.cpp

@@ -136,7 +136,7 @@ void cass_session_get_metrics(const CassSession* session, CassMetrics* metrics)
   metrics->stats.exceeded_pending_requests_water_mark = 0;                 // Deprecated
 
   metrics->errors.connection_timeouts = internal_metrics->connection_timeouts.sum();
-  metrics->errors.pending_request_timeouts = internal_metrics->pending_request_timeouts.sum();
+  metrics->errors.pending_request_timeouts = 0; // Deprecated
   metrics->errors.request_timeouts = internal_metrics->request_timeouts.sum();
 }
 

tests/src/integration/tests/test_metrics.cpp

@@ -76,28 +76,6 @@ CASSANDRA_INTEGRATION_TEST_F(MetricsTests, ErrorsConnectionTimeouts) {
   EXPECT_GE(2u, metrics.errors.connection_timeouts);
 }
 
-/**
- * This test ensures that the driver is reporting the proper timeouts for pending requests
- *
- * @since 2.0.0
- * @jira_ticket CPP-188
- */
-CASSANDRA_INTEGRATION_TEST_F(MetricsTests, ErrorsPendingRequestTimeouts) {
-  CHECK_FAILURE;
-  CHECK_VERSION(2.1.2);
-
-  for (int n = 0; n < 1000; ++n) {
-    session_.execute_async(SELECT_ALL_SYSTEM_LOCAL_CQL);
-  }
-
-  CassMetrics metrics = session_.metrics();
-  for (int i = 0; i < 100 && metrics.errors.pending_request_timeouts == 0; ++i) {
-    metrics = session_.metrics();
-    msleep(100);
-  }
-  EXPECT_GT(metrics.errors.pending_request_timeouts, 0u);
-}
-
 /**
  * This test ensures that the driver is reporting the proper timeouts for requests
  *