Diskless sync delay is now configurable.

src/config.c

@@ -274,6 +274,12 @@ void loadServerConfigFromString(char *config) {
             if ((server.repl_diskless_sync = yesnotoi(argv[1])) == -1) {
                 err = "argument must be 'yes' or 'no'"; goto loaderr;
             }
+        } else if (!strcasecmp(argv[0],"repl-diskless-sync-delay") && argc==2) {
+            server.repl_diskless_sync_delay = atoi(argv[1]);
+            if (server.repl_diskless_sync_delay < 0) {
+                err = "repl-diskless-sync-delay can't be negative";
+                goto loaderr;
+            }
         } else if (!strcasecmp(argv[0],"repl-backlog-size") && argc == 2) {
             long long size = memtoll(argv[1],NULL);
             if (size <= 0) {
@@ -920,6 +926,10 @@ void configSetCommand(redisClient *c) {
 
         if (yn == -1) goto badfmt;
         server.repl_diskless_sync = yn;
+    } else if (!strcasecmp(c->argv[2]->ptr,"repl-diskless-sync-delay")) {
+        if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
+            ll < 0) goto badfmt;
+        server.repl_diskless_sync_delay = ll;
     } else if (!strcasecmp(c->argv[2]->ptr,"slave-priority")) {
         if (getLongLongFromObject(o,&ll) == REDIS_ERR ||
             ll < 0) goto badfmt;
@@ -1058,6 +1068,7 @@ void configGetCommand(redisClient *c) {
     config_get_numerical_field("cluster-node-timeout",server.cluster_node_timeout);
     config_get_numerical_field("cluster-migration-barrier",server.cluster_migration_barrier);
     config_get_numerical_field("cluster-slave-validity-factor",server.cluster_slave_validity_factor);
+    config_get_numerical_field("repl-diskless-sync-delay",server.repl_diskless_sync_delay);
 
     /* Bool (yes/no) values */
     config_get_bool_field("cluster-require-full-coverage",
@@ -1804,6 +1815,7 @@ int rewriteConfig(char *path) {
     rewriteConfigBytesOption(state,"repl-backlog-ttl",server.repl_backlog_time_limit,REDIS_DEFAULT_REPL_BACKLOG_TIME_LIMIT);
     rewriteConfigYesNoOption(state,"repl-disable-tcp-nodelay",server.repl_disable_tcp_nodelay,REDIS_DEFAULT_REPL_DISABLE_TCP_NODELAY);
     rewriteConfigYesNoOption(state,"repl-diskless-sync",server.repl_diskless_sync,REDIS_DEFAULT_REPL_DISKLESS_SYNC);
+    rewriteConfigNumericalOption(state,"repl-diskless-sync-delay",server.repl_diskless_sync_delay,REDIS_DEFAULT_REPL_DISKLESS_SYNC_DELAY);
     rewriteConfigNumericalOption(state,"slave-priority",server.slave_priority,REDIS_DEFAULT_SLAVE_PRIORITY);
     rewriteConfigNumericalOption(state,"min-slaves-to-write",server.repl_min_slaves_to_write,REDIS_DEFAULT_MIN_SLAVES_TO_WRITE);
     rewriteConfigNumericalOption(state,"min-slaves-max-lag",server.repl_min_slaves_max_lag,REDIS_DEFAULT_MIN_SLAVES_MAX_LAG);

src/redis.c

@@ -1481,6 +1481,7 @@ void initServerConfig(void) {
     server.repl_down_since = 0; /* Never connected, repl is down since EVER. */
     server.repl_disable_tcp_nodelay = REDIS_DEFAULT_REPL_DISABLE_TCP_NODELAY;
     server.repl_diskless_sync = REDIS_DEFAULT_REPL_DISKLESS_SYNC;
+    server.repl_diskless_sync_delay = REDIS_DEFAULT_REPL_DISKLESS_SYNC_DELAY;
     server.slave_priority = REDIS_DEFAULT_SLAVE_PRIORITY;
     server.master_repl_offset = 0;
 

src/redis.h

@@ -802,6 +802,7 @@ struct redisServer {
     int repl_min_slaves_max_lag;    /* Max lag of <count> slaves to write. */
     int repl_good_slaves_count;     /* Number of slaves with lag <= max_lag. */
     int repl_diskless_sync;         /* Send RDB to slaves sockets directly. */
+    int repl_diskless_sync_delay;   /* Delay to start a diskless repl BGSAVE. */
     /* Replication (slave) */
     char *masterauth;               /* AUTH with this password with master */
     char *masterhost;               /* Hostname of master */

src/replication.c

@@ -2034,9 +2034,9 @@ void replicationCron(void) {
             }
         }
 
-        if (slaves_waiting && max_idle > REDIS_DEFAULT_REPL_DISKLESS_SYNC_DELAY)
-        {
-            /* Let's start a BGSAVE with disk target. */
+        if (slaves_waiting && max_idle > server.repl_diskless_sync_delay) {
+            /* Start a BGSAVE. Usually with socket target, or with disk target
+             * if there was a recent socket -> disk config change. */
             if (startBgsaveForReplication() == REDIS_OK) {
                 /* It started! We need to change the state of slaves
                  * from WAIT_BGSAVE_START to WAIT_BGSAVE_END. */