Stash saving on :get and :set performance benefits?

Question

I'm still trying to fully wrap my brain around Stash's cacheing system.

From the docs it seems that both :set and :get have the parameters save, scope, replace, and refresh.

Is there a benefit to using both?

I had thought that perhaps saving on set could be used to store raw data and saving on get could be used to store formatted data. So for example:

{exp:stash:set_list name="products" parse_tags="yes" 
 save="yes" refresh="60" replace="no" scope="site"}
    {exp:low_variables:pair var="lv_products"}
        {stash:prod_image}{image}{/stash:prod_image}
        {stash:prod_url}{link}{/stash:prod_url}
        {stash:prod_title}{link_title}{/stash:prod_title}
    {/exp:low_variables:pair}
{/exp:stash:set_list}

And then:

{exp:stash:get_list:nested name="products"
 save="yes" refresh="60" replace="no" scope="site"}
{if count == 1}<ul>{/if}
    <li><a href="{other_prod_url}">{other_prod_image} <b>{other_prod_title}</b></a></li>
{/if count == total_results}</ul>{/if}
{/exp:stash:get_list:nested}

In a more "real world" example. I have a rather complex drop-down navigation that is built off nav:ee but includes low variables with playa, and matrix to create "mega-dropdowns" I stash each bit of data individually, but then also tried to stash the entire generated menu with the page uri as a context.

Is this a correct/beneficial "layered caching" approach? Or am I missing something here? :)

Answer 1

For the {exp:stash:get} tag save is only used with dynamic="yes" when retrieving dynamic values from $_POST, $_GET or segment arrays.

For your menu it only makes sense to stash the parts of your menu as separate lists if you are re-using those values elsewhere. Otherwise, just wrap the tags that generate the menu with a {exp:stash:set} with the output parameter set to yes so you don't need to get it:

{exp:stash:set name="main_menu" save="yes" scope="site" replace="no" output="yes" refresh="0"}
[various expensive tags that generate the menu]
{/exp:stash:set}

If this is a main menu then it would be wasteful to cache a unique instance for each page URI. If you need the menu markup to change to display an active state - based on the value of {segment_1} for example - then enclose the relevant conditionals with {stash:nocache} tag pairs to escape them from caching.