Spotfire Server: Attachment Manager Cache FAQ

The following are frequently asked questions about Spotfire Server's Attachment Manager caching functionality.

If we disable the AttachmentManager cache, how will it affect the system, how will the data stream be handled?

The attachment manager cache is mainly used when you open from library or saving large amounts of data. Therefore -  disabling cache will result in extra work for the library database.

Please note - disabling attachment manager cache will not stop temporary files from being created in that location. Disabling cache only stops caching data fetched from Spotfire library and information link results. Disabling attachment manager cache will only reduce the size of AttachmentManager folder size by size of the cache (which is around 10 GB by default). 

However, for normal functionality of Spotfire, the Attachment Manager still needs to function, as attachments are created as soon as "data" is downloaded from or uploaded to the Spotfire Server. The creation of these attachments is essential for the operation of the Spotfire Server and cannot be disabled.

This documentation page describes several settings for Attachment Manager:

https://docs.tibco.com/pub/spotfire_server/14.0.6/doc/html/TIB_sfire_server_tsas_admin_help/server/topics/attachment_manager_cache.html

It is possible to disable Attachment Manager cache:

https://docs.tibco.com/pub/spotfire_server/14.0.6/doc/html/TIB_sfire_server_tsas_admin_help/server/topics/disabling_the_attachment_manager_cache.html

How does data flow of Information Links work - will it first be fully stored as a temp file by the AttachmentManager and then passed to Analyst or Web Player?

The data flow for information links will not be affected by disabling AttachmentManager cache - the data will still go through the Spotfire Server (and Attachment Manager) and then get passed to Analyst or Web Player, not as a single large temp file, but in small parts, which are later removed, if you have not enabled caching on that information link (or disabled Attachment Manager cache).

Setting information services caching to false will mean that the results of information link executions are not being stored, on global level, even if you have caching enabled on individual information link level. 

When disabling the AttachmentManager cache will the data go to the JVM? If yes, what are the risks of getting more GC?

Disabling attachment manager cache should have no influence on JVM and GC for activity related to information links.
 

What is a normal size for the AttachementManager folder?

The files that you see related to Attachment Manager depend mostly how you use Spotfire - a different number can be normal for different use cases. If Spotfire Server is configured to cache Information Links and library content, this uses additional disk space. By default, caching is enabled and the max cache size set to 10 GB. And expiration time is 24 hours by default.

You can set Attachment Manager cache settings using config-attachment-manager command:

https://docs.tibco.com/pub/spotfire_server/14.0.6/doc/html/TIB_sfire_server_tsas_admin_help/server/topics/config-attachment-manager.html

The max-cache-expiration-time value is the maximum idle time (in seconds) after which cache entries are evicted. Setting this parameter to a negative value disables the cache. 

The max-cache-size value is the maximum amount of disk space (in megabytes) used by the cache. Setting this parameter to a negative value disables the cache.

Attachments are created as soon as "data" is downloaded from or uploaded to Spotfire Server. The data may either be library items or the results of Information Link executions (and a few other much less frequent operations). The creation of these attachments is essential for the operation of the Spotfire Server and cannot be disabled.

The primary goal of Attachment Manager is to reduce data latency and workload on databases - the Spotfire Server database or Information Services data sources. By default, all library items (Spotfire Server database) that are downloaded or uploaded are cached. The results of Information Link executions (Information Services data sources) can also be cached, but this needs to be enabled per Information Link, since for Information Links, unlike library items, we do not have a general way of detecting if the cached data is stale or not.
 

We see older files then today in the AttachmentManager folder, when will it clean up?

By default, items will be evicted from the cache if they've been idle for more than 24 hours, or if a new item is added and there is no more room in the cache (based on the configured maximum size - which by default is 10240 MB). In the latter case, the least recently used items are evicted.

As for old items being present, that is fully expected if those items are frequently requested and, thus, they never becomes idle or stale.
 

What happens if the disk is full and the AttachmentManager cannot write?

In general, not enough disk space will be problematic for the functionality of Spotfire Server. It is important to set max-cache-size to a value that will not cause disk space issues.