Re: [Cppcms-users] managing caching with lists

[Artyom <art...@ya...>]

> From: Andrew <an...@bu...>
> 
> Hi all,
> 
> so I have a table of item records, each of which can be viewed,  edited and 
>updated by id.
> 
> /item/view/{item id}
> /item/edit/{item  id}
> /item/update/{item id}
> 
> I also have a controller that provides a  list view
> 
> /list/{page no}
> 
> 
> managing the caching for the item  views is easy enough, I give each page a 
>trigger that looks  like
> 
> cache().add_trigger("item_{item id}")
> 
> and refresh the cache  when the item is updated
> 
> cache().rise("item_{item id}")
> 
> 
> but I  am having trouble finding a non-complicated way to
> manage the caching of the  list view, I have solved it
> temporarily by simply refreshing every page
> in the  list entirely whenever an item is updated,
> but ideally I would like to find a  simple algorithm that
> lets me only refresh the cache for the page on which the
> item that has been updated appears.
> 

You have a /list/{page no}

item_1, item_2, item_3. for /list/page/1
item_4, item_5, item_6. for /list/page/2

And so on.

So for each page you add a trigger just like




> because items are ordered by date  modified,
> and can be added or deleted, which page the
> item appears on will  change frequently.
> 
> does anyone have a solution that they have found works
> for this kind of scenario?
> 

The point is that deleting an item that for example
at the top of the list may change all pages i.e.

item_1, item_3, item_4,  /list/page/1
item_5, item_6, item_7   /list/page/2

So in case of adding new item ore removing
new item list rise "list_general" and all pages
would be clean and of course add_trigger "list_general"
to all the pages.

So basically for each page


  for id in range
    add_trigger iterm_{id}
    add_trigger list_general

And when you update an item_id

on UPDATE id

  rise(item_{id})

on Add/Delete id

  rise(item_{id})
  rise(list_general)

This is how I work with the cache of the
blog where multiple pages exist.

Of course if the items are added and removed
too frequently and you don't want to throw
away all the cache you should consider using
timeouts and have some not fully consistent
cache.


> thanks all :)
> 


Best,
  Artyom

>