Cache That Can Purge Unused Objects by Demand

Can squid proxy's cache overflow?

I think i got the answer for my question.

Squid uses LRU cache replacement policy to discard old/unused cache objects.

http://www.squid-cache.org/Doc/config/cache_replacement_policy/

Python in-memory cache with time to live

You can use the expiringdict module:

The core of the library is ExpiringDict class which is an ordered dictionary with auto-expiring values for caching purposes.

In the description they do not talk about multithreading, so in order not to mess up, use a Lock.

Identifying Unused Objects In Microsoft SQL Server 2005

With SQL Server 2005, you can use the dynamic management view sys.dm_db_index_usage_stats. The name says "index" but that's a little misleading - every table has an entry in here, even if it doesn't have any indexes. Here's a useful query from SQL Magazine:

SELECT 
  t.name AS 'Table', 
  SUM(i.user_seeks + i.user_scans + i.user_lookups) 
    AS 'Total accesses',
  SUM(i.user_seeks) AS 'Seeks',
  SUM(i.user_scans) AS 'Scans',
  SUM(i.user_lookups) AS 'Lookups'
FROM 
  sys.dm_db_index_usage_stats i RIGHT OUTER JOIN 
    sys.tables t ON (t.object_id = i.object_id)
GROUP BY 
  i.object_id, 
  t.name
ORDER BY [Total accesses] DESC

Here's the original article:

http://www.sqlmag.com/Article/ArticleID/53878/sql_server_53878.html

Keep in mind that these usage statistics reset when SQL Server restarts.

Clear the Cache Scope and Private object store in Mule 4

I have raised a support ticket with Mulesoft and received the below replies

1) Invalidate Cache is shown only in the palette from the Anypoint Studio Version 7.4.1. Not shown in earlier version of studio.( I was using 7.3.2)

2) They are adding the documentation for the invalidate cache in Mule 4.

3) Usage Note : Cache Scope and the 'Invalidate Cache' processor should share the same Caching_Strategy).

4) In order to explicitly define object store and ttl for a Cache Scope, please ensure object store related modules are added to the project.
This can be done by simply adding a 'Store' processor in your mule flow, this will add all necessary modules to your mule application.
Then, on the Caching Strategy, General > Reference > Object Store, you can select Edit Inline and define your object store with explicit settings such as
- Max entries
- Entry ttl
- Expiration interval
You can remove the unused 'Store' processor as well.

Hope it helps others

Does the garbage collector thrashes stale required modules from memory in NodeJS?

Node's documentation on modules says they're cached (doesn't seem different in the v5 docs either), and doesn't suggest any mechanism by which the cache releases its reference to the module. As long as there is a reference to the module (e.g., in the caching mechanism), it will be retained in memory, like any other JavaScript object.

Is homescreen addition (A2H) ever a signal for browsers to defer PWA cache purging when storage runs low?

I'm not aware of "add to home screen" being used as a signal when determining whether or not to clear an origin's storage when a device is running out of space. I wouldn't rely on it one way or another.

Instead, there's a web platform feature known as "Persistent Storage" that you can use to explicitly request that your origin's storage not be purged due to space constraints. That's something you could rely on with greater certainty. From that article:

Beginning with Chrome 55, Chrome will automatically grant the
persistence permission if any of the following are true:

• The site is bookmarked (and the user has 5 or less bookmarks)
• The site has high site engagement
• The site has been added to home screen
• The site has push notifications enabled

The permission is automatically denied in all other cases. The goal is
to ensure that users can rely on their favorite web apps and not find
they have suddenly been cleared.

You'd use it like:

if (navigator.storage && navigator.storage.persist) {
  navigator.storage.persist().then((granted) => {
    // Optionally update your UI based on the granted state.
  });
}

How to clear gradle cache?

As @Bradford20000 pointed out in the comments, there might be a gradle.properties file as well as global gradle scripts located under $HOME/.gradle. In such case special attention must be paid when deleting the content of this directory.

The .gradle/caches directory holds the Gradle build cache. So if you have any error about build cache, you can delete it.

The --no-build-cache option will run gradle without the build cache.

Daemon on MS Windows
If you're on Windows, you'll need to kill the daemon before it allows you to clear those directories. See Kill all Gradle Daemons Regardless Version? for more info.

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