清漆缓存 - 缓存页面的时间长度？

Question

I have a doubt regarding the working of vanish cache. I installed the varnish cache with my apache web sever and configured the same correctly, so that I can access web pages through varnish cache.

The question is here, that I have created a 'test.php' page and this can be accessed through browser. I have changed the content of the page and immediately after again accessed the same page through browser. The second time it was showing the changed content. Why it is so? Up to my knowledge, the second time also it should show the old content (?); because varnish cache will retain contents of web pages for a shot interval. Is there any settings that I need to change? Please advice.

Thank You.

Answer 1

If your seeing the latest contents each time you refresh then you haven't set varnish up properly.

Varnish should sit on a different port to Apache so make sure your visiting test.php on the varnish port.

You can put this in your config to see if it's caching..

sub vcl_deliver {
    # Add a header to indicate a cache HIT/MISS
    if (obj.hits > 0) {
        set resp.http.X-Cache = "HIT";
    } else {
        set resp.http.X-Cache = "MISS";
    }
    return (deliver);
}

If you see the X-Cache header then you know it's at least running through varnish.

Answer 2

The http headers you're setting in your pages play a great role to decide whether they will be cached or not. Read the varnish documentation about this

Answer 3

This thread looks old. But this value can be found in the vanish config set the value for VARNISH_TTL

# # Default TTL used when the backend does not specify one
VARNISH_TTL= 120

The default is 120 seconds I am sure you can change it from that point