Lua scripts for efficient batch counting and removing keys.

src/Orchard.Web/Modules/Orchard.Redis/Extensions/RedisDatabaseExtensions.cs

@@ -0,0 +1,42 @@
+using System;
+using StackExchange.Redis;
+
+namespace Orchard.Redis.Extensions
+{
+    public static class RedisDatabaseExtensions
+    {
+        public static void KeyDeleteWithPrefix(this IDatabase database, string prefix)
+        {
+            if (database == null) {
+                throw new ArgumentException("Database cannot be null", "database");
+            }
+
+            if (string.IsNullOrWhiteSpace(prefix)) {
+                throw new ArgumentException("Prefix cannot be empty", "database");
+            }
+
+            database.ScriptEvaluate(@"
+                local keys = redis.call('keys', ARGV[1]) 
+                for i=1,#keys,5000 do 
+                redis.call('del', unpack(keys, i, math.min(i+4999, #keys)))
+                end", values: new RedisValue[] { prefix });
+        }
+
+        public static int KeyCount(this IDatabase database, string prefix) {
+            if (database == null) {
+                throw new ArgumentException("Database cannot be null", "database");
+            }
+
+            if (string.IsNullOrWhiteSpace(prefix)) {
+                throw new ArgumentException("Prefix cannot be empty", "database");
+            }
+
+            var retVal = database.ScriptEvaluate("return table.getn(redis.call('keys', ARGV[1]))", values: new RedisValue[] { prefix });
+
+            if (retVal.IsNull)
+                return 0;
+
+            return (int)retVal;
+        }
+    }
+}

src/Orchard.Web/Modules/Orchard.Redis/Orchard.Redis.csproj

@@ -101,6 +101,7 @@
     </ProjectReference>
   </ItemGroup>
   <ItemGroup>
+    <Compile Include="Caching\RedisDatabaseExtensions.cs" />
     <Compile Include="Configuration\IRedisConnectionProvider.cs" />
     <Compile Include="Configuration\RedisConnectionProvider.cs" />
     <Compile Include="MessageBus\RedisMessageBusBroker.cs" />