安卓java post-image限制64kb mysql blob

我正试图将用相机拍摄的图像POST到一个PHP脚本中，该脚本将POST保存到MySQL表中。

    Bitmap bm = BitmapFactory.decodeFile(imageurl);
    StringBuilder postDataBuilder = new StringBuilder();
    postDataBuilder.append("[Notas]").append("=").append(URLEncoder.encode(etReclamo.getText().toString(), Constants.UTF8));
    postDataBuilder.append("&").append("image").append("=").append(URLEncoder.encode(getStringImage(bm), Constants.UTF8));
    final byte[] postData = postDataBuilder.toString().getBytes(Constants.UTF8);
    new AsyncTask(){
        @Override
        protected Object doInBackground(Object[] params) {
            try{
                URL url = new URL(Constants.URL_RECLAMO);
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setDoOutput(true);
                conn.setUseCaches(false);
                conn.setFixedLengthStreamingMode(postData.length);
                conn.setRequestMethod("POST");
                conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
                OutputStream out = conn.getOutputStream();
                out.write(postData);
                InputStream is = conn.getInputStream();
                resultado = IOUtils.toString(is);
                out.close();
                int status = conn.getResponseCode();
                if (status == 200) {
                    handler.sendEmptyMessage(RESPUESTA_HTTP_EXITO);
                } else {
                    handler.sendEmptyMessage(RESPUESTA_HTTP_ERROR);
                    throw new IOException("Request failed with error code "
                            + status);
                }
            } catch (IOException e) {
                Log.e("RECLAMO", "IOError");
            }
            return null;
        }
    }.execute(null, null, null);
}

发送字符串没有问题，但我不能存储超过64KB的内容。为什么？

我在MySQL中尝试过BLOB和TEXT类型。发送和不发送流长度。