optimize: use LuaJIT v2.1's new table.new API to optimize Lua table a…

…llocations. when table.new is missing, just fall back to the good old "{}". this gives 12% overall speedup for a typical result set with 500 rows. feature: added an optional new argument "est_rows" to the query() and read_result() methods.
openresty · Oct 13, 2013 · 5811773 · 5811773
1 parent 5b5b9b2
commit 5811773
Showing 1 changed file with 23 additions and 12 deletions.
diff --git a/lib/resty/mysql.lua b/lib/resty/mysql.lua
@@ -23,6 +23,12 @@ local error = error
 local tonumber = tonumber
 
 
+local ok, new_tab = pcall(require, "table.new")
+if not ok then
+    new_tab = function (narr, nrec) return {} end
+end
+
+
 local _M = { _VERSION = '0.13' }
 
 
@@ -43,7 +49,7 @@ local mt = { __index = _M }
 
 
 -- mysql field value type converters
-local converters = {}
+local converters = new_tab(0, 8)
 
 for i = 0x01, 0x05 do
     -- tiny, short, long, float, double
@@ -127,8 +133,8 @@ end
 
 
 local function _dump(data)
-    local bytes = {}
     local len = #data
+    local bytes = new_tab(len, 0)
     for i = 1, len do
         bytes[i] = strbyte(data, i)
     end
@@ -137,8 +143,8 @@ end
 
 
 local function _dumphex(data)
-    local bytes = {}
     local len = #data
+    local bytes = new_tab(len, 0)
     for i = 1, len do
         bytes[i] = tohex(strbyte(data, i), 2)
     end
@@ -154,8 +160,8 @@ local function _compute_token(password, scramble)
     local stage1 = sha1(password)
     local stage2 = sha1(stage1)
     local stage3 = sha1(scramble .. stage2)
-    local bytes = {}
     local n = #stage1
+    local bytes = new_tab(n, 0)
     for i = 1, n do
          bytes[i] = strchar(bxor(strbyte(stage3, i), strbyte(stage1, i)))
     end
@@ -283,7 +289,7 @@ end
 
 
 local function _parse_ok_packet(packet)
-    local res = {}
+    local res = new_tab(0, 5)
     local pos
 
     res.affected_rows, pos = _from_length_coded_bin(packet, 2)
@@ -350,7 +356,7 @@ end
 
 
 local function _parse_field_packet(data)
-    local col = {}
+    local col = new_tab(0, 2)
     local catalog, db, table, orig_table, orig_name, charsetnr, length
     local pos
     catalog, pos = _from_length_coded_str(data, 1)
@@ -391,9 +397,14 @@ end
 
 
 local function _parse_row_data_packet(data, cols, compact)
-    local row = {}
     local pos = 1
     local ncols = #cols
+    local row
+    if compact then
+        row = new_tab(ncols, 0)
+    else
+        row = new_tab(0, ncols)
+    end
     for i = 1, ncols do
         local value
         value, pos = _from_length_coded_str(data, pos)
@@ -714,7 +725,7 @@ end
 _M.send_query = send_query
 
 
-local function read_result(self)
+local function read_result(self, est_nrows)
     if self.state ~= STATE_COMMAND_SENT then
         return nil, "cannot read result in the current context: " .. self.state
     end
@@ -760,7 +771,7 @@ local function read_result(self)
 
     --print("field count: ", field_count)
 
-    local cols = {}
+    local cols = new_tab(field_count, 0)
     for i = 1, field_count do
         local col, err, errno, sqlstate = _recv_field_packet(self)
         if not col then
@@ -784,7 +795,7 @@ local function read_result(self)
 
     local compact = self.compact
 
-    local rows = {}
+    local rows = new_tab(est_nrows or 4, 0)
     local i = 0
     while true do
         --print("reading a row")
@@ -824,13 +835,13 @@ end
 _M.read_result = read_result
 
 
-function _M.query(self, query)
+function _M.query(self, query, est_nrows)
     local bytes, err = send_query(self, query)
     if not bytes then
         return nil, "failed to send query: " .. err
     end
 
-    return read_result(self)
+    return read_result(self, est_nrows)
 end