optimize redis compose_message, see redistest for changes

test case: start redistest

examples/redistest.lua

@@ -0,0 +1,53 @@
+local skynet = require "skynet"
+local redis  = require "redis"
+
+local db
+
+function add1(key, count)
+    local t = {}
+    for i = 1, count do
+        t[2*i -1] = "key" ..i
+        t[2*i] = "value" .. i
+    end
+    db:hmset(key, table.unpack(t))
+end
+
+function add2(key, count)
+    local t = {}
+    for i = 1, count do
+        t[2*i -1] = "key" ..i
+        t[2*i] = "value" .. i
+    end
+    table.insert(t, 1, key)
+    db:hmset(t)
+end
+
+function __init__()
+    db = redis.connect {
+        host = "127.0.0.1",
+        port = 6300,
+        db   = 0,
+        auth = "foobared"
+    }
+    print("dbsize:", db:dbsize())
+    local ok, msg = xpcall(add1, debug.traceback, "test1", 250000)
+    if not ok then
+        print("add1 failed", msg)
+    else
+        print("add1 succeed")
+
+    end
+
+    local ok, msg = xpcall(add2, debug.traceback, "test2", 250000)
+    if not ok then
+        print("add2 failed", msg)
+    else
+        print("add2 succeed")
+    end
+    print("dbsize:", db:dbsize())
+
+    print("redistest launched")
+end
+
+skynet.start(__init__)
+