From e9e007555e03af906544c0870faaaba1e1d2d0a2 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Thu, 16 Oct 2014 09:03:52 +0200
Subject: [PATCH] Diskless replication: trigger diskless RDB transfer if
 needed.

---
 src/redis.h       |  2 +-
 src/replication.c | 37 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/redis.h b/src/redis.h
index e5581436..fd491b45 100644
--- a/src/redis.h
+++ b/src/redis.h
@@ -115,7 +115,7 @@ typedef long long mstime_t; /* millisecond time type. */
 #define REDIS_DEFAULT_RDB_CHECKSUM 1
 #define REDIS_DEFAULT_RDB_FILENAME "dump.rdb"
 #define REDIS_DEFAULT_RDB_DISKLESS 0
-#define REIDS_DEFAULT_RDB_DISKLESS_DELAY 5
+#define REDIS_DEFAULT_RDB_DISKLESS_DELAY 5
 #define REDIS_DEFAULT_SLAVE_SERVE_STALE_DATA 1
 #define REDIS_DEFAULT_SLAVE_READ_ONLY 1
 #define REDIS_DEFAULT_REPL_DISABLE_TCP_NODELAY 0
diff --git a/src/replication.c b/src/replication.c
index 02d4d50b..11ed3a91 100644
--- a/src/replication.c
+++ b/src/replication.c
@@ -212,7 +212,7 @@ void replicationFeedSlaves(list *slaves, int dictid, robj **argv, int argc) {
     }
 
     /* Write the command to every slave. */
-    listRewind(slaves,&li);
+    listRewind(server.slaves,&li);
     while((ln = listNext(&li))) {
         redisClient *slave = ln->value;
 
@@ -1941,6 +1941,41 @@ void replicationCron(void) {
         replicationScriptCacheFlush();
     }
 
+    /* If we are using diskless replication and there are slaves waiting
+     * in WAIT_BGSAVE_START state, check if enough seconds elapsed and
+     * start one. */
+    if (server.repl_diskless && server.rdb_child_pid == -1 &&
+        server.aof_child_pid == -1)
+    {
+        time_t idle, max_idle = 0;
+        int slaves_waiting = 0;
+        listNode *ln;
+        listIter li;
+
+        listRewind(server.slaves,&li);
+        while((ln = listNext(&li))) {
+            redisClient *slave = ln->value;
+            if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START) {
+                idle = server.unixtime - slave->lastinteraction;
+                if (idle > max_idle) max_idle = idle;
+                slaves_waiting++;
+            }
+        }
+
+        if (slaves_waiting && max_idle > REDIS_DEFAULT_RDB_DISKLESS_DELAY) {
+            /* Let's start a BGSAVE with disk target. */
+            if (startBgsaveForReplication() == REDIS_OK) {
+                /* It started! We need to change the state of slaves
+                 * from WAIT_BGSAVE_START to WAIT_BGSAVE_END. */
+                while((ln = listNext(&li))) {
+                    redisClient *slave = ln->value;
+                    if (slave->replstate == REDIS_REPL_WAIT_BGSAVE_START)
+                        slave->replstate = REDIS_REPL_WAIT_BGSAVE_END;
+                }
+            }
+        }
+    }
+
     /* Refresh the number of slaves with lag <= min-slaves-max-lag. */
     refreshGoodSlavesCount();
 }