Gtmetrix shows high loading time for first domain waiting time. How to reduce it

Question

I am wondering, why is my Domain taking long time to load?
As per Gtmetrix timeline, first domain name propagation takes up to 953ms:

Blocking - 53 ms
Waiting - 843 ms
Receiving - 57 ms

Sometimes its takes up to even 2 seconds.

Below is response from Header:

Server              Apache/2.2
Vary                Accept-Encoding
Cache-Control       no-cache
Content-Type        text/html; charset=utf-8
Content-Encoding    gzip
P3P                 CP="NOI ADM DEV PSAi COM NAV OUR OTRo STP IND DEM"
Date                Wed, 22 Jan 2014 02:45:14 GMT
Pragma              no-cache
Connection          Keep-Alive
Set-Cookie          X-Mapping-alncmkhk=EDDD5D603AF7261BACF2EBF3FC8185A8; path=/
ed2f1641e2a81373908380a3799b0d29=59n2seqdchc1j6lvl48lepevg0; path=/
Content-Length      7806

Request Headers    
Host                www.mycarhelpline.com
User-Agent          Mozilla/5.0 (X11; Linux i686 on x86_64; rv:25.0) Gecko/20100101 Firefox/25.0
Accept              text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language     en-US,en;q=0.5
Accept-Encoding     gzip, deflate
Connection          keep-alive

Any advice - what to do correctly to decrease this substantially by over 90%?

Answer 1

The Waiting time is the big problem here. This is the time your web server takes to generate the HTML page once it has received the request. Long waiting times are generally a result of the server needing to do a lot of processing to create the page - for example fetching information from a database or from an external web service.

EDIT: You need to find out whether the delays are caused by plugins or are due to your hosting company. You should put your police detective hat on and do some investigating:) Start by creating a very basic page and taking the timings for it to load. Then add plugins and turn on features one at a time until you discover what is taking so much time. If a very simple page with no plugins enabled is taking way too long then you may need to change your web hosting company. You can use the developer tools (press F12) in modern browsers to get the loading times shown in a Network tab, and it is the Waiting time for the very first request of each page that you need to inspect.

I'm guessing that the "Ask A Question Forum" section pulls its data from somewhere every time the page is requested and this is causing the delay. If so you will need to find ways to optimize the time this takes and/or to use some kind of caching strategy. Personally I would get the server to grab the necessary data in the background at maybe 5 minute intervals and store it in memory. Then when the server needs to generate the page it can just include the data from memory which is super mega quick. You may be able to get the server to update this cached data every time the forum is updated so its available almost instantly.

If you are calling a database then I would also spend some time optimizing the queries used - proper indexing can make a massive speed difference. Also if your database is at a different location to your web server then you will have extra delays from sending/receiving data between the two. This makes it even more important to only read from the database when you really need to. Also only fetch the exact data you need - make sure you are not bringing back every record and every column in that record, the query results should only contain the minimum information that you need.