Cache Control
- Thomas Timbul
Price Checker 2 caches some API results to improve performance for subsequent runs.
The Cache Control screen allows you to empty/reset these caches on demand, as well as adjusting retention settings, including the maximum amount of time data may be kept for and the maximum amount of space they are allowed to use on disk.
What does caching mean in practice?
The cache is like a short term memory. It allows certain information to be taken from that memory instead of looking it up from the (slower) API again. This comes at the cost of having (possibly) stale data.
Any requests for the same data for the same ASIN (or Brand in the case of Brand Listing Restrictions) made within the retention period is allowed to use data from the original lookup. So with the settings shown above the review count figure for a particular product may be up to 30 days old, but ONLY IF the product had been run through your particular installation of Price Checker 2 within the past 30 days.
Type | What is cached? |
|---|---|
Reviews | Results from “Get Variation Reviews”, i.e. count and rating per variation when used. For browser runs or when using historical data*: count/rating on a product level (not per variation. (*Independent of other historical data, see below) |
Historical | All historical data previously downloaded for an ASIN. This includes historical averages, out of stock percentages, etc. Because historical data continues to be updated, the default timeframe is deliberately chosen quite short (3 days = 10% of a month). |
Inbound Eligibility / Hazmat | The outcome of checking for eligibility, i.e. if any issues prevent an item from being shipped into FBA in the first place. If an item is classified as Hazmat/under review and therefore non-shippable, or it has missing information in the listing, this information is less likely to change very frequently. |
ASIN Listing Restrictions | Seller-specific restrictions specific to an individual ASIN. This is where Amazon does not provide a reason beyond “You need permission to sell this item”. This information is not going to change unless you go through the process of requesting authorization, so considering that its lookup is one of the slowest operations in the pipeline, considerable time savings can be made here. |
Brand Listing Restrictions | Seller-specific restrictions where a brand has been mentioned. If you are not authorized to sell a certain brand (i.e. ‘gated’), all products from the same brand (same spelling and capitalisation) can also be marked as requiring authorization without spending the time to look it up fresh. This has an immediate impact even within the same run. |
Making changes to the cache configuration
To edit cache retention settings, simply edit as you desire on the Cache Control screen and press “Save”.
“Retain for up to” controls the length of time that each item is allowed to be remembered for. If this is exceeded, the item will be “evicted” and looked up fresh if and when the next time it features in your run.
“Max Size” controls the amount of space that all information together is allowed to use on disk. If this space is exceeded, the least recently used record is “evicted” first.
To force fresh lookup of the information, you can empty a cache by pressing the bin/trash can button. Please note that there is no confirmation prompt when using this option.
Considerations
Please remember that other than the Listing Restrictions caches, most caching benefits re-runs of the exact same ASINs and has little to no effect unless products repeat within the caching period. So if you run the same list of products once a week and are happy with some data (e.g. the review count) being slightly out of date, you would benefit.
On the other hand, if you have reviews set to cache for 7 days, but only re-run the same list once a month, PC2 would always need to fetch them again.
You will need to balance the time saving against any possible drawbacks arising from not using the freshest data.
Any data points not mentioned above are always retrieved fresh. This includes mapping products codes to ASINs and live offer information.