Unshare object to avoid LRU/LFU being messed up.

Signed-off-by: chentianjie.ctj <[email protected]>
CharlesChen888 · Apr 7, 2024 · 73395f3 · 73395f3
1 parent 717ec1e
commit 73395f3
Show file tree

Hide file tree

Showing 3 changed files with 10 additions and 2 deletions.
diff --git a/src/db.c b/src/db.c
@@ -125,6 +125,10 @@ robj *lookupKey(serverDb *db, robj *key, int flags) {
             server.current_client->cmd->proc != touchCommand)
             flags |= LOOKUP_NOTOUCH;
         if (!hasActiveChildProcess() && !(flags & LOOKUP_NOTOUCH)){
+            if (!canUseSharedObject() && val->refcount == OBJ_SHARED_REFCOUNT) {
+                val = dupStringObject(val);
+                kvstoreDictSetVal(db->keys, getKeySlot(key->ptr), de, val);
+            }
             if (server.maxmemory_policy & MAXMEMORY_FLAG_LFU) {
                 updateLFU(val);
             } else {

diff --git a/src/object.c b/src/object.c
@@ -631,6 +631,10 @@ void trimStringObjectIfNeeded(robj *o, int trim_small_values) {
     }
 }
 
+int canUseSharedObject(void) {
+    return server.maxmemory == 0 || !(server.maxmemory_policy & MAXMEMORY_FLAG_NO_SHARED_INTEGERS);
+}
+
 /* Try to encode a string object in order to save space */
 robj *tryObjectEncodingEx(robj *o, int try_trim) {
     long value;
@@ -662,8 +666,7 @@ robj *tryObjectEncodingEx(robj *o, int try_trim) {
          * Note that we avoid using shared integers when maxmemory is used
          * because every object needs to have a private LRU field for the LRU
          * algorithm to work well. */
-        if ((server.maxmemory == 0 ||
-            !(server.maxmemory_policy & MAXMEMORY_FLAG_NO_SHARED_INTEGERS)) &&
+        if (canUseSharedObject() &&
             value >= 0 &&
             value < OBJ_SHARED_INTEGERS)
         {

diff --git a/src/server.h b/src/server.h
@@ -2808,6 +2808,7 @@ int collateStringObjects(const robj *a, const robj *b);
 int equalStringObjects(robj *a, robj *b);
 unsigned long long estimateObjectIdleTime(robj *o);
 void trimStringObjectIfNeeded(robj *o, int trim_small_values);
+int canUseSharedObject(void);
 #define sdsEncodedObject(objptr) (objptr->encoding == OBJ_ENCODING_RAW || objptr->encoding == OBJ_ENCODING_EMBSTR)
 
 /* Synchronous I/O with timeout */