[8.0] Tweaking the current_connections metric

db/appsock_handler.c

@@ -55,6 +55,8 @@ char appsock_unknown_old[] = "-1 #unknown command\n";
 char appsock_unknown[] = "Error: -1 #unknown command\n";
 char appsock_supported[] = "supported\n";
 int32_t active_appsock_conns = 0;
+int32_t pooled_appsock_conns = 0; /* number of connections owned by sockpool or local-cache */
+int32_t appsock_conns = 0;
 int64_t gbl_denied_appsock_connection_count = 0;
 
 pthread_mutex_t appsock_conn_lk = PTHREAD_MUTEX_INITIALIZER;
@@ -113,6 +115,7 @@ void appsock_quick_stat(void)
 {
     logmsg(LOGMSG_USER, "num appsock connections %llu\n", total_appsock_conns);
     logmsg(LOGMSG_USER, "num active appsock connections %d\n", active_appsock_conns);
+    logmsg(LOGMSG_USER, "num pooled appsock connections %d\n", pooled_appsock_conns);
     logmsg(LOGMSG_USER, "num appsock commands    %llu\n", total_toks);
 }
 
@@ -352,8 +355,8 @@ void appsock_handler_start(struct dbenv *dbenv, SBUF2 *sb, int admin)
 
             logmsg(
                 LOGMSG_WARN,
-                "%s: Maximum appsock connection limit approaching (%d/%d).\n",
-                __func__, active_appsock_conns, max);
+                "%s: Maximum appsock connection limit approaching (%d/%d/%d).\n",
+                __func__, (active_appsock_conns - pooled_appsock_conns), active_appsock_conns, max);
             lastprint = now;
 
             if ((now - last_thread_dump_time) > 10) {

db/db_metrics.c

@@ -570,7 +570,8 @@ int refresh_metrics(void)
     stats.sql_cost = gbl_nsql_steps + gbl_nnewsql_steps;
     stats.sql_count = gbl_nsql + gbl_nnewsql;
     stats.sql_ssl_count = gbl_nnewsql_ssl;
-    stats.current_connections = net_get_num_current_non_appsock_accepts(thedb->handle_sibling) + active_appsock_conns;
+    stats.current_connections = net_get_num_current_non_appsock_accepts(thedb->handle_sibling) +
+                                (active_appsock_conns - pooled_appsock_conns);
 
     rc = bdb_get_lock_counters(thedb->bdb_env, &stats.deadlocks,
                                &stats.locks_aborted, &stats.lockwaits,

db/sqlinterfaces.c

@@ -6065,6 +6065,10 @@ static const char* connstate_str(enum connection_state s) {
 void clnt_change_state(struct sqlclntstate *clnt, enum connection_state state) {
     clnt->state_start_time = comdb2_time_epochms();
     Pthread_mutex_lock(&clnt->state_lk);
+    if (clnt->state == CONNECTION_RESET && state != CONNECTION_RESET)
+        ATOMIC_ADD32(pooled_appsock_conns, -1);
+    else if (clnt->state != CONNECTION_RESET && state == CONNECTION_RESET)
+        ATOMIC_ADD32(pooled_appsock_conns, 1);
     clnt->state = state;
     Pthread_mutex_unlock(&clnt->state_lk);
 }

net/net_appsock.h

@@ -36,6 +36,7 @@ typedef void(*run_on_base_fn)(void *);
 void run_on_base(struct event_base *, run_on_base_fn, void *);
 
 extern int32_t active_appsock_conns;
+extern int32_t pooled_appsock_conns;
 extern int64_t gbl_denied_appsock_connection_count;
 extern int gbl_libevent_appsock;
 

plugins/newsql/newsql_evbuffer.c

@@ -114,6 +114,8 @@ static void free_newsql_appdata_evbuffer(int dummyfd, short what, void *arg)
 {
     struct newsql_appdata_evbuffer *appdata = arg;
     struct sqlclntstate *clnt = &appdata->clnt;
+    if (clnt->state == CONNECTION_RESET)
+        ATOMIC_ADD32(pooled_appsock_conns, -1);
     int fd = appdata->fd;
     rem_sql_evbuffer(clnt);
     rem_appsock_connection_evbuffer(clnt);

tests/comdb2sys.test/runit

@@ -128,6 +128,11 @@ rc2=$?
 
 ./testtransactionstate $a_dbn
 rc3=$?
+
+./test_current_connections $a_dbn
+rc4=$?
+
+[[ $rc4 -ne 0 ]] && rc3=$rc4
 [[ $rc3 -ne 0 ]] && rc2=$rc3 
 [[ $rc2 -ne 0 ]] && rc=$rc2
 

tests/comdb2sys.test/test_current_connections

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+DB=$1
+default=default
+cdb2sql=cdb2sql
+set -e
+
+hostflags=
+
+if [[ -n "$CLUSTER" ]]; then
+    read -ra nodes <<< "$CLUSTER"
+    hostflags="--host ${nodes[0]}"
+fi
+
+
+sql='SELECT SLEEP(2)'
+for i in $(seq 1 10); do
+    $cdb2sql ${CDB2_OPTIONS} $hostflags $DB $default "$sql" &
+done
+
+wait
+
+n=`$cdb2sql --tabs ${CDB2_OPTIONS} $hostflags $DB $default "SELECT value FROM comdb2_metrics WHERE name='current_connections'"`
+if [[ $n -ne 1 ]]; then
+    echo current_connections $n >&2
+    exit 1
+fi
+
+echo $(basename $0) success
+exit 0

tests/comdb2sys.test/testtransactionstate

@@ -24,4 +24,7 @@ if [[ $rc -ne 0  ]]; then
     echo "Failed transaction state test"
 fi
 
+wait
+cdb2sql ${CDB2_OPTIONS} $a_dbn --host $master 'put tunable debug.txn_sleep = 0'
+
 exit $rc