From 99c2fe0bcf9876daf774fa7df4939cadc7972129 Mon Sep 17 00:00:00 2001
From: Dvir Volk <dvirsky@google.com>
Date: Thu, 21 Mar 2019 11:47:14 +0200
Subject: [PATCH] added special flag for keyspace miss notifications

---
 src/db.c                 | 6 +++---
 src/modules/testmodule.c | 2 +-
 src/notify.c             | 6 ++++--
 src/redismodule.h        | 1 +
 src/server.h             | 4 +++-
 5 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/db.c b/src/db.c
index 8c9047084..afe181281 100644
--- a/src/db.c
+++ b/src/db.c
@@ -107,7 +107,7 @@ robj *lookupKeyReadWithFlags(redisDb *db, robj *key, int flags) {
          * to return NULL ASAP. */
         if (server.masterhost == NULL) {
             server.stat_keyspace_misses++;
-            notifyKeyspaceEvent(NOTIFY_GENERIC, "miss", key, db->id);
+            notifyKeyspaceEvent(NOTIFY_KEY_MISS, "miss", key, db->id);
             return NULL;
         }
 
@@ -129,14 +129,14 @@ robj *lookupKeyReadWithFlags(redisDb *db, robj *key, int flags) {
             server.current_client->cmd->flags & CMD_READONLY)
         {
             server.stat_keyspace_misses++;
-            notifyKeyspaceEvent(NOTIFY_GENERIC, "miss", key, db->id);
+            notifyKeyspaceEvent(NOTIFY_KEY_MISS, "miss", key, db->id);
             return NULL;
         }
     }
     val = lookupKey(db,key,flags);
     if (val == NULL) {
         server.stat_keyspace_misses++;
-        notifyKeyspaceEvent(NOTIFY_GENERIC, "miss", key, db->id);
+        notifyKeyspaceEvent(NOTIFY_KEY_MISS, "miss", key, db->id);
     }
     else
         server.stat_keyspace_hits++;
diff --git a/src/modules/testmodule.c b/src/modules/testmodule.c
index 826dd9a7e..af78d21d7 100644
--- a/src/modules/testmodule.c
+++ b/src/modules/testmodule.c
@@ -450,7 +450,7 @@ int RedisModule_OnLoad(RedisModuleCtx *ctx, RedisModuleString **argv, int argc)
                                             REDISMODULE_NOTIFY_HASH |
                                             REDISMODULE_NOTIFY_SET |
                                             REDISMODULE_NOTIFY_STRING |
-                                            REDISMODULE_NOTIFY_GENERIC,
+                                            REDISMODULE_NOTIFY_KEY_MISS,
                                         NotifyCallback);
     if (RedisModule_CreateCommand(ctx,"test.notify",
         TestNotifications,"write deny-oom",1,1,1) == REDISMODULE_ERR)
diff --git a/src/notify.c b/src/notify.c
index 1afb36fc0..d6c3ad403 100644
--- a/src/notify.c
+++ b/src/notify.c
@@ -55,6 +55,7 @@ int keyspaceEventsStringToFlags(char *classes) {
         case 'K': flags |= NOTIFY_KEYSPACE; break;
         case 'E': flags |= NOTIFY_KEYEVENT; break;
         case 't': flags |= NOTIFY_STREAM; break;
+        case 'm': flags |= NOTIFY_KEY_MISS; break;
         default: return -1;
         }
     }
@@ -81,6 +82,7 @@ sds keyspaceEventsFlagsToString(int flags) {
         if (flags & NOTIFY_EXPIRED) res = sdscatlen(res,"x",1);
         if (flags & NOTIFY_EVICTED) res = sdscatlen(res,"e",1);
         if (flags & NOTIFY_STREAM) res = sdscatlen(res,"t",1);
+        if (flags & NOTIFY_KEY_MISS) res = sdscatlen(res,"m",1);
     }
     if (flags & NOTIFY_KEYSPACE) res = sdscatlen(res,"K",1);
     if (flags & NOTIFY_KEYEVENT) res = sdscatlen(res,"E",1);
@@ -100,12 +102,12 @@ void notifyKeyspaceEvent(int type, char *event, robj *key, int dbid) {
     int len = -1;
     char buf[24];
 
-    /* If any modules are interested in events, notify the module system now. 
+    /* If any modules are interested in events, notify the module system now.
      * This bypasses the notifications configuration, but the module engine
      * will only call event subscribers if the event type matches the types
      * they are interested in. */
      moduleNotifyKeyspaceEvent(type, event, key, dbid);
-    
+
     /* If notifications for this class of events are off, return ASAP. */
     if (!(server.notify_keyspace_events & type)) return;
 
diff --git a/src/redismodule.h b/src/redismodule.h
index 272da08df..681bd600b 100644
--- a/src/redismodule.h
+++ b/src/redismodule.h
@@ -98,6 +98,7 @@
 #define REDISMODULE_NOTIFY_EXPIRED (1<<8)     /* x */
 #define REDISMODULE_NOTIFY_EVICTED (1<<9)     /* e */
 #define REDISMODULE_NOTIFY_STREAM (1<<10)     /* t */
+#define REDISMODULE_NOTIFY_KEY_MISS (1<<11)   /* m */
 #define REDISMODULE_NOTIFY_ALL (REDISMODULE_NOTIFY_GENERIC | REDISMODULE_NOTIFY_STRING | REDISMODULE_NOTIFY_LIST | REDISMODULE_NOTIFY_SET | REDISMODULE_NOTIFY_HASH | REDISMODULE_NOTIFY_ZSET | REDISMODULE_NOTIFY_EXPIRED | REDISMODULE_NOTIFY_EVICTED | REDISMODULE_NOTIFY_STREAM)      /* A */
 
 
diff --git a/src/server.h b/src/server.h
index 56c3b67d3..0b433039d 100644
--- a/src/server.h
+++ b/src/server.h
@@ -468,7 +468,9 @@ typedef long long mstime_t; /* millisecond time type. */
 #define NOTIFY_EXPIRED (1<<8)     /* x */
 #define NOTIFY_EVICTED (1<<9)     /* e */
 #define NOTIFY_STREAM (1<<10)     /* t */
-#define NOTIFY_ALL (NOTIFY_GENERIC | NOTIFY_STRING | NOTIFY_LIST | NOTIFY_SET | NOTIFY_HASH | NOTIFY_ZSET | NOTIFY_EXPIRED | NOTIFY_EVICTED | NOTIFY_STREAM) /* A flag */
+#define NOTIFY_KEY_MISS (1<<11)   /* m */
+
+#define NOTIFY_ALL (NOTIFY_GENERIC | NOTIFY_STRING | NOTIFY_LIST | NOTIFY_SET | NOTIFY_HASH | NOTIFY_ZSET | NOTIFY_EXPIRED | NOTIFY_EVICTED | NOTIFY_STREAM | NOTIFY_KEY_MISS) /* A flag */
 
 /* Get the first bind addr or NULL */
 #define NET_FIRST_BIND_ADDR (server.bindaddr_count ? server.bindaddr[0] : NULL)