What's the recommended way to handle users making changes on production?

[stephenmeehanuk]

Hi

I've setup Redis and queues - which work great when I deploy changes. Pages are nicely cached.

But the site often 504s, this seems to coincide with when the client makes updates to the site.

The site isn't constantly throwing 504s, so I'm reasonably confident this is the reason.

It's a big site, and many pages are fairly 'meaty', they really benefit from being cached.

I've got a bunch of invalidation rules, which essentially clear the page cache (or most of it) anytime a change is made.

What I think is happening

When then site is being edited, the page cache is cleared, during this time the site is still being visited. But the first visit is uncached, and I'm seeing timeouts.

Sometimes there could be two users making edits to different parts of the website at the same time. Every time an edit is saved the invalidation rules clear the cache.

So there's this temporary storm every couple of days when the site 504s for a bit.

Does this sound likely?

What can I do?

I can see there's a STATAMIC_GIT_DISPATCH_DELAY=10config, but how does that work? I assume this is related to just Git commits? And wouldn't help with the page cache issue?

Is there a way to delay all updates to the site and run them all in one hit at a quiet time of day?

Any suggestions, ideas would be most welcome :)

[edalzell]

What are your invalidation rules?

[stephenmeehanuk]

Hi Erin,

Thinking about it, I perhaps have two options:

Scheduled Cache Rebuilding
Stop the invalidation entirely and rebuild cache at set times

Or

Reduce invalidation rules
Dramatically reduce what gets cleared

Instead of constantly trying to rebuild the page cache only to have it cleared moments later by a user making an edit, perhaps page cache needs to be a scheduled event?

The site has lots of references to other parts of the site, for example every /rail page shows the latest three news stories etc. Maybe every page doesn't have to show the very latest news stories...

But looking at these rules, perhaps they can be reduced so not as much of the page cache is cleared each time an entry is updated. I'll look into it.

Keen to get your thoughts on this.

I'm also running a cron job every minute.

php /home/ploi/website.com/artisan schedule:run

Here's my invalidation rules.

'invalidation' => [

        'class' => null,

        'rules' => [
            'collections' => [                
                'news_and_events' => [
                    'urls' => [
                        '/', 
                        '/news',                    
                        '/news/*', 
                        '/rail',                    
                        '/rail/*',                    
                        '/infrastructure',                    
                        '/infrastructure/*',                   
                    ]
                ],  
                'products' => [
                    'urls' => [
                        '/', 
                        '/rail',                    
                        '/rail/*',                    
                        '/infrastructure',                    
                        '/infrastructure/*',                    
                    ]
                ], 
                'executive_leadership' => [
                    'urls' => [
                        '/about/leadership',                                    
                    ]
                ], 
                'case_studies' => [
                    'urls' => [
                        '/case-studies',                    
                        '/case-studies/*',                    
                    ]
                ],  
                'pages' => [
                    'urls' => [
                        '/',                    
                        '/about',                    
                        '/about/*',                    
                        '/purpose',                    
                        '/purpose/*',                    
                    ]
                ],                         
                'sales' => [
                    'urls' => [
                        '/contact/regional-representatives',
                        '/rail/*',
                        '/infrastructure/*',                                     
                    ]
                ],              
                'sales_offices' => [
                    'urls' => [
                        '/rail/*',
                        '/infrastructure/*',                                       
                    ]
                ],              
            ],             
            'navigation' => [
                'main_menu_v2' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
                'corporate' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
                'footer_about' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
                'footer_products' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
                'footer_useful_links' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
                'legal_menu' => [
                    'urls' => [
                        '/*'
                    ]
                ], 
            ],  
            'globals' => [
                'company' => [
                    'urls' => [
                        '/*'
                    ]
                ],
                'seo' => [
                    'urls' => [
                        '/*'
                    ]
                ],
                'referer_source' => [
                    'urls' => [
                        '/*'
                    ]
                ]
            ],        
        ],

[stephenmeehanuk]

Or maybe both?

Reduce the invalidation rules so it doesn't try to rebuild every page, just the main ones e.g

'invalidation' => [
    'rules' => [
        'collections' => [
            'news_and_events' => [
                'urls' => [
                    '/',           // Just homepage
                    '/news',       // Just news index
                    // Remove the /rail/* and /infrastructure/* wildcards
                ]
            ],
        ],
        ... rest of rules
    ],
],

And schedule a full cache rebuild at a set time per day.

[edalzell]

Use Ryan's cache invalidation addon, and why do you do a full scheduled cache clear?

[edalzell]

https://github.com/thoughtco/statamic-cache-tracker

[aaronbushnell]

Silly question, @stephenmeehanuk, but I'm curious what your hosting situation is? Are you able to profile the site to determine what pages are the most problematic and performance-intensive?

I've ran into similar situations with other frameworks and CMSs and I've found the most ideal solution is either:

• Finding big optimization opportunities
• Scaling up the VPS to be more tolerant