COPY and REPLACE options for MIGRATE.

With COPY now MIGRATE does not remove the key from the source instance.
With REPLACE it uses RESTORE REPLACE on the target host so that even if
the key already eixsts in the target instance it will be overwritten.

The options can be used together.

diff --git a/src/cluster.c b/src/cluster.c
index 33a267589ff945d589c64d508323de8d41e9183f..3d758276ad9739ff36d9c0221f685521dd53d7c0 100644 (file)
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -1595,15 +1595,27 @@ void restoreCommand(redisClient *c) {
     server.dirty++;
 }
 
-/* MIGRATE host port key dbid timeout */
+/* MIGRATE host port key dbid timeout [COPY | REPLACE] */
 void migrateCommand(redisClient *c) {
-    int fd;
+    int fd, copy = 0, replace = 0, j;
     long timeout;
     long dbid;
     long long ttl = 0, expireat;
     robj *o;
     rio cmd, payload;
 
+    /* Parse additional options */
+    for (j = 6; j < c->argc; j++) {
+        if (!strcasecmp(c->argv[j]->ptr,"copy")) {
+            copy = 1;
+        } else if (!strcasecmp(c->argv[j]->ptr,"replace")) {
+            replace = 1;
+        } else {
+            addReply(c,shared.syntaxerr);
+            return;
+        }
+    }
+
     /* Sanity check */
     if (getLongFromObjectOrReply(c,c->argv[5],&timeout,NULL) != REDIS_OK)
         return;
@@ -1643,19 +1655,24 @@ void migrateCommand(redisClient *c) {
         ttl = expireat-mstime();
         if (ttl < 1) ttl = 1;
     }
-    redisAssertWithInfo(c,NULL,rioWriteBulkCount(&cmd,'*',4));
+    redisAssertWithInfo(c,NULL,rioWriteBulkCount(&cmd,'*',replace ? 5 : 4));
     redisAssertWithInfo(c,NULL,rioWriteBulkString(&cmd,"RESTORE",7));
     redisAssertWithInfo(c,NULL,c->argv[3]->encoding == REDIS_ENCODING_RAW);
     redisAssertWithInfo(c,NULL,rioWriteBulkString(&cmd,c->argv[3]->ptr,sdslen(c->argv[3]->ptr)));
     redisAssertWithInfo(c,NULL,rioWriteBulkLongLong(&cmd,ttl));
 
-    /* Finally the last argument that is the serailized object payload
-     * in the DUMP format. */
+    /* Emit the payload argument, that is the serailized object using
+     * the DUMP format. */
     createDumpPayload(&payload,o);
     redisAssertWithInfo(c,NULL,rioWriteBulkString(&cmd,payload.io.buffer.ptr,
                                 sdslen(payload.io.buffer.ptr)));
     sdsfree(payload.io.buffer.ptr);
 
+    /* Add the REPLACE option to the RESTORE command if it was specified
+     * as a MIGRATE option. */
+    if (replace)
+        redisAssertWithInfo(c,NULL,rioWriteBulkString(&cmd,"REPLACE",7));
+
     /* Tranfer the query to the other node in 64K chunks. */
     {
         sds buf = cmd.io.buffer.ptr;
@@ -1686,8 +1703,11 @@ void migrateCommand(redisClient *c) {
         } else {
             robj *aux;
 
-            dbDelete(c->db,c->argv[3]);
-            signalModifiedKey(c->db,c->argv[3]);
+            if (!copy) {
+                /* No COPY option: remove the local key, signal the change. */
+                dbDelete(c->db,c->argv[3]);
+                signalModifiedKey(c->db,c->argv[3]);
+            }
             addReply(c,shared.ok);
             server.dirty++;
 

diff --git a/src/redis.c b/src/redis.c
index 0780e8876b4f5bbb2e618d1de50709106f8988f6..1dcca1fd25fb57c6df8ef6c62550d376dec3e3a8 100644 (file)
--- a/src/redis.c
+++ b/src/redis.c
@@ -241,7 +241,7 @@ struct redisCommand redisCommandTable[] = {
     {"unwatch",unwatchCommand,1,"rs",0,NULL,0,0,0,0,0},
     {"cluster",clusterCommand,-2,"ar",0,NULL,0,0,0,0,0},
     {"restore",restoreCommand,-4,"awm",0,NULL,1,1,1,0,0},
-    {"migrate",migrateCommand,6,"aw",0,NULL,0,0,0,0,0},
+    {"migrate",migrateCommand,-6,"aw",0,NULL,0,0,0,0,0},
     {"asking",askingCommand,1,"r",0,NULL,0,0,0,0,0},
     {"dump",dumpCommand,2,"ar",0,NULL,1,1,1,0,0},
     {"object",objectCommand,-2,"r",0,NULL,2,2,2,0,0},

diff --git a/tests/unit/dump.tcl b/tests/unit/dump.tcl
index 1eb91eb21842571067e84474cbd817d9d94efe96..202098da2b5ef8a473952b0d378aeb40026b06d9 100644 (file)
--- a/tests/unit/dump.tcl
+++ b/tests/unit/dump.tcl
@@ -62,6 +62,47 @@ start_server {tags {"dump"}} {
         }
     }
 
+    test {MIGRATE is able to copy a key between two instances} {
+        set first [srv 0 client]
+        r del list
+        r lpush list a b c d
+        start_server {tags {"repl"}} {
+            set second [srv 0 client]
+            set second_host [srv 0 host]
+            set second_port [srv 0 port]
+
+            assert {[$first exists list] == 1}
+            assert {[$second exists list] == 0}
+            set ret [r -1 migrate $second_host $second_port list 9 5000 copy]
+            assert {$ret eq {OK}}
+            assert {[$first exists list] == 1}
+            assert {[$second exists list] == 1}
+            assert {[$first lrange list 0 -1] eq [$second lrange list 0 -1]}
+        }
+    }
+
+    test {MIGRATE will not overwrite existing keys, unless REPLACE is used} {
+        set first [srv 0 client]
+        r del list
+        r lpush list a b c d
+        start_server {tags {"repl"}} {
+            set second [srv 0 client]
+            set second_host [srv 0 host]
+            set second_port [srv 0 port]
+
+            assert {[$first exists list] == 1}
+            assert {[$second exists list] == 0}
+            $second set list somevalue
+            catch {r -1 migrate $second_host $second_port list 9 5000 copy} e
+            assert_match {ERR*} $e
+            set res [r -1 migrate $second_host $second_port list 9 5000 copy replace]
+            assert {$ret eq {OK}}
+            assert {[$first exists list] == 1}
+            assert {[$second exists list] == 1}
+            assert {[$first lrange list 0 -1] eq [$second lrange list 0 -1]}
+        }
+    }
+
     test {MIGRATE propagates TTL correctly} {
         set first [srv 0 client]
         r set key "Some Value"