feature: support pass table to send_query

README.markdown

@@ -286,6 +286,8 @@ send_query
 
 Sends the query to the remote MySQL server without waiting for its replies.
 
+The argument query can be a string or a (nested) Lua table holding string fragments.
+
 Returns the bytes successfully sent out in success and otherwise returns `nil` and a string describing the error.
 
 You should use the [read_result](#read_result) method to read the MySQL replies afterwards.

lib/resty/mysql.lua

@@ -120,6 +120,11 @@ converters[0x09] = tonumber  -- int24
 converters[0x0d] = tonumber  -- year
 converters[0xf6] = tonumber  -- newdecimal
 
+-- avoid extra allocation of temp tables by sharing preallocated tables
+local packet = new_tab(3, 0)
+local query_packet = new_tab(2, 0)
+query_packet[1] = strchar(COM_QUERY)
+
 
 local function _get_byte2(data, i)
     local a, b = strbyte(data, i, i + 1)
@@ -230,18 +235,43 @@ local function _compute_token(password, scramble)
 end
 
 
+local function _compute_size(a)
+    -- compute total size of a string or a (nested) Lua table holding string fragments
+    if type(a) == "string" then
+        return #a
+    end
+    local n = 0
+    for i, v in ipairs(a) do
+        n = n + _compute_size(v)
+    end
+    return n
+end
+
+
+local function _concat_rec(t, sep)
+    for i, v in ipairs(t) do
+        if type(v) == "table" then
+            t[i] = _concat_rec(v, sep)
+        end
+    end
+    return concat(t, sep)
+end
+
+
 local function _send_packet(self, req, size)
     local sock = self.sock
 
     self.packet_no = self.packet_no + 1
 
     -- print("packet no: ", self.packet_no)
 
-    local packet = _set_byte3(size) .. strchar(band(self.packet_no, 255)) .. req
+    packet[1] = _set_byte3(size)
+    packet[2] = strchar(band(self.packet_no, 255))
+    packet[3] = req
 
-    -- print("sending packet: ", _dump(packet))
+    -- print("sending packet: ", _dump(_concat_rec(packet)))
 
-    -- print("sending packet... of size " .. #packet)
+    -- print("sending packet... of size " .. _compute_size(packet))
 
     return sock:send(packet)
 end
@@ -805,10 +835,9 @@ local function send_query(self, query)
 
     self.packet_no = -1
 
-    local cmd_packet = strchar(COM_QUERY) .. query
-    local packet_len = 1 + #query
-
-    local bytes, err = _send_packet(self, cmd_packet, packet_len)
+    local packet_len = 1 + _compute_size(query)
+    query_packet[2] = query
+    local bytes, err = _send_packet(self, query_packet, packet_len)
     if not bytes then
         return nil, err
     end

t/sanity.t

@@ -1321,3 +1321,81 @@ success
 --- no_error_log
 [error]
 --- timeout: 20
+
+
+
+=== TEST 20: query with a table
+--- http_config eval: $::HttpConfig
+--- config
+    location /t {
+        content_by_lua '
+            local ljson = require "ljson"
+
+            local mysql = require "resty.mysql"
+            local db = mysql:new()
+
+            db:set_timeout(2000) -- 2 sec
+
+            local ok, err, errno, sqlstate = db:connect({
+                host = "$TEST_NGINX_MYSQL_HOST",
+                port = $TEST_NGINX_MYSQL_PORT,
+                database = "ngx_test",
+                user = "ngx_test",
+                password = "ngx_test"})
+
+            if not ok then
+                ngx.say("failed to connect: ", err, ": ", errno, " ", sqlstate)
+                return
+            end
+
+            ngx.say("connected to mysql.")
+
+            local res, err, errno, sqlstate = db:query("drop table if exists cats")
+            if not res then
+                ngx.say("bad result: ", err, ": ", errno, ": ", sqlstate, ".")
+                return
+            end
+
+            ngx.say("table cats dropped.")
+
+            res, err, errno, sqlstate = db:query("create table cats (id serial primary key, name varchar(5))")
+            if not res then
+                ngx.say("bad result: ", err, ": ", errno, ": ", sqlstate, ".")
+                return
+            end
+
+            ngx.say("table cats created.")
+
+            res, err, errno, sqlstate = db:query({"insert into ", "cats (name) value ", {"(\'Bob\'),", "(\'\'),", "(null)"}})
+            if not res then
+                ngx.say("bad result: ", err, ": ", errno, ": ", sqlstate, ".")
+                return
+            end
+
+            ngx.say(res.affected_rows, " rows inserted into table cats (last id: ", res.insert_id, ")")
+
+            res, err, errno, sqlstate = db:query({"select * from ", "cats", " order by id asc"})
+            if not res then
+                ngx.say("bad result: ", err, ": ", errno, ": ", sqlstate, ".")
+                return
+            end
+
+            ngx.say("result: ", ljson.encode(res))
+
+            local ok, err = db:close()
+            if not ok then
+                ngx.say("failed to close: ", err)
+                return
+            end
+        ';
+    }
+--- request
+GET /t
+--- response_body
+connected to mysql.
+table cats dropped.
+table cats created.
+3 rows inserted into table cats (last id: 1)
+result: [{"id":"1","name":"Bob"},{"id":"2","name":""},{"id":"3","name":null}]
+--- no_error_log
+[error]