Replication: added new stats counting full and partial resynchronizations.

src/redis.c

@@ -1384,6 +1384,9 @@ void initServer() {
     server.stat_peak_memory = 0;
     server.stat_fork_time = 0;
     server.stat_rejected_conn = 0;
+    server.stat_sync_full = 0;
+    server.stat_sync_partial_ok = 0;
+    server.stat_sync_partial_err = 0;
     memset(server.ops_sec_samples,0,sizeof(server.ops_sec_samples));
     server.ops_sec_idx = 0;
     server.ops_sec_last_sample_time = mstime();
@@ -2128,6 +2131,9 @@ sds genRedisInfoString(char *section) {
             "total_commands_processed:%lld\r\n"
             "instantaneous_ops_per_sec:%lld\r\n"
             "rejected_connections:%lld\r\n"
+            "sync_full:%lld\r\n"
+            "sync_partial_ok:%lld\r\n"
+            "sync_partial_err:%lld\r\n"
             "expired_keys:%lld\r\n"
             "evicted_keys:%lld\r\n"
             "keyspace_hits:%lld\r\n"
@@ -2140,6 +2146,9 @@ sds genRedisInfoString(char *section) {
             server.stat_numcommands,
             getOperationsPerSecond(),
             server.stat_rejected_conn,
+            server.stat_sync_full,
+            server.stat_sync_partial_ok,
+            server.stat_sync_partial_err,
             server.stat_expiredkeys,
             server.stat_evictedkeys,
             server.stat_keyspace_hits,

src/redis.h

@@ -691,6 +691,9 @@ struct redisServer {
     size_t stat_peak_memory;        /* Max used memory record */
     long long stat_fork_time;       /* Time needed to perform latest fork() */
     long long stat_rejected_conn;   /* Clients rejected because of maxclients */
+    long long stat_sync_full;       /* Number of full resyncs with slaves. */
+    long long stat_sync_partial_ok; /* Number of accepted PSYNC requests. */
+    long long stat_sync_partial_err;/* Number of unaccepted PSYNC requests. */
     list *slowlog;                  /* SLOWLOG list of commands */
     long long slowlog_entry_id;     /* SLOWLOG current entry ID */
     long long slowlog_log_slower_than; /* SLOWLOG time limit (to get logged) */

src/replication.c

@@ -490,8 +490,23 @@ void syncCommand(redisClient *c) {
      *
      * So the slave knows the new runid and offset to try a PSYNC later
      * if the connection with the master is lost. */
-    if (!strcasecmp(c->argv[0]->ptr,"psync") &&
-        masterTryPartialResynchronization(c) == REDIS_OK) return;
+    if (!strcasecmp(c->argv[0]->ptr,"psync")) {
+        if (masterTryPartialResynchronization(c) == REDIS_OK) {
+            server.stat_sync_partial_ok++;
+            return; /* No full resync needed, return. */
+        } else {
+            char *master_runid = c->argv[1]->ptr;
+            
+            /* Increment stats for failed PSYNCs, but only if the
+             * runid is not "?", as this is used by slaves to force a full
+             * resync on purpose when they are not albe to partially
+             * resync. */
+            if (master_runid[0] != '?') server.stat_sync_partial_err++;
+        }
+    }
+
+    /* Full resynchronization. */
+    server.stat_sync_full++;
 
     /* Here we need to check if there is a background saving operation
      * in progress, or if it is required to start one */