Sharing a cache in Adobe Bridge

Using Adobe Bridge as a means of archiving and accessing a digital asset library accessed by multiple users has always been a somewhat clunky affair. Each time the library was updated, users had to update their locally stored image cache.  Well, no more!

If you're using the latest version of Adobe Bridge you're in luck -- multiple users can now share caches which reduces lag time in accessing images and also reduces hard drive space on each machine. Just go to Tools>Cache>Manage Cache.

To learn all about sharing the cache in Bridge visit the Adobe website.

Note: for users of Adobe Bridge CC 2018 and earlier you're stuck with the old method. Sorry.

Adobe Bridge new caching system

The caching system used by Adobe in its image asset manager Bridge is the very heart of the program. If you don't understand it thoroughly you should, and if you do, well, now is the time to take a look at the changes they have made in the latest iteration of Bridge.

For me, one of the most disconcerting aspects of the latest version is its attempt to want to purge and/or optimize the cache. In older versions you had to do this manually, but now it can actually be set to perform the task regularly. And if you use Bridge to archive lots of photos this could spell real trouble. Unless, of course, you have have the latest version of Bridge which allows you to export/share/import caches.

You find the cache details in Preferences: Bridge>Preferences>Cache. That should also give you the precise location of the cache file(s) on your machine.

Anyway, be extra-careful and be sure to check out Adobe's website for more information on the cache, purging it and optimizing the cache in Bridge.

I'll deal with the new sharing cache feature in tomorrow's post.

Export cache to Folders

OK, so the long and short of this feature of Adobe Bridge is, it works.  
Since I manage a library used by a couple of dozen users, I never use this feature since it can't be shared. But I recently upgraded my Windows machine to Bridge 6.2 and experienced a somewhat troubling when I went to index a copy of the image library I had on an external hard drive.

A few weeks back I uploaded a complete copy of our image library onto an external hard drive, which included nearly 300k of photos taking up some 1.8 tbs of space. I chose to index this external drive copy of the library using the "Prefer Embedded" rather than "Always High Quality” in generating the metadata t speed up the caching process and discovered soon after that the cache was gone, or rather it had not indexed properly. Either way, no search results were coming up.Whatever it was, I was faced with how to resolve this potentially disastrous issue.


 So, since I was using the copy of the library I had on an external drive I thought why not try the "Export Cache to Folders" feature? After all, I didn’t need to rebuild the cache on my local machine since I was the only one accessing the external drive.

I selected the Image Library at the topmost level and chose “Export Cache to Folders.” After about 36 hours it had completely built a cache file in each and every one of 164 folders. As a result, searching is quick and spot on. And I don’t have to rely on the nuances of Bridge’s own cache on the machine itself.

One caveat, though: I don’t know what the consequences would be if you moved the image library to a new drive. Would Bridge still read the cache in each folder? My guess is it shouldn’t make a difference and Adobe claims it should still work fine. Still, I’ll have to test that out, but using a much smaller and more manageable sample.

For the moment, however, if you’re the only one using your image library use the “Export Cache to Folders” feature.

Bridge encounters a problem reading the cache -- solution - 1/28/2016

OK, so a fresh install of the program did NOT help. The problem with Bridge was beginning to appear systemic. It was occurring whether connected to the network through VPN, to an external hard drive on my desk or when trying to access a folder on my PC desktop.

Well, after some online research I think I might have found the solution: restore the program's factory settings. That is, reset the Preferences and purge the thumbnail cache.

According to Adobe you launch Bridge and IMMEDIATELY hold down the Command+Option+Shift (PC: Control+Alt+Shift) keys. A small dialogue box will appear:

Check the two boxes as shown and voila! You should be all set. A word of caution, though. This will, of course reset all your Preferences so you will have to tweak Bridge . and you'll have to reindex your image library, too. The word online is that this might happen with some frequency. We'll see.

Bridge encounters a problem reading the cache

OK, so right off I want to emphasize that this is a BIG and I mean very big PROBLEM. Aside from Bridge's painfully slow search feature - however robust it might -- the potential for a corrupt cache is very real, particularly for the archivist who is a heavy Bridge user.

You launch Bridge and when normally the program opens and stabilizes you see it stall out as it "builds criteria" even though you've selected nothing. That means its trying to access the cache of the interface itself and having a damn hard time doing it.

Then you get the dreaded message: "Bridge encountered a problem reading the cache. Please purge the central cache."

Oh no.

That means all the indexing you've done has to be trashed and you need to start all over again. Which also means that you are unable to search your image library in the process. That's not good.

Well, this has happened to me a number of times over the years and it's never pretty. While you can't prevent this from happening you can anticipate that it will and work around it.

How?

Always have the image library indexed on at least two machines. That's what I do and if you're using Bridge to manage an image library you should, too.

Speed up your indexing in Bridge

If you find yourself having to reindex/recache an extremely large image library (like ours), here's a handy tip to get you back in search mode fast.

1. Launch Bridge
2. Make sure Path Bar is visible (if not, go to Window>Path Bar).
3. On the right side of the Path Bar, just to the left of the Star rating drop-down menu are two square icons. These allow you to modify the thumbnail quality and preview generation in Bridge. 
4. Select "Prefer Embedded (Faster)".
5. Voila!

It might take a few moments when you select an image to generate a preview and if you find this too annoying you can change it back to "Always High Quality" or even  add "Generate 100% Previews" although this will consume lots more disk space and of course take more time in caching/indexing)

Cache workaround if you have to update/upgrade Bridge

Upgrading your present version of Bridge will require a completely new cache for your image library. (Indeed, each version of Bridge is cache specific.) If you need the latest version of Bridge to help keep up with your design teams but don't want to have to completely reindex your image library there is one reliable workaround: Don't do it.

OK, what I mean is keep your "old" version of Bridge and use that for all your searching needs -- you're already indexed. After all, the latest version probably won't make a significant difference for searching. You can still upgrade, of course, just don't overwrite your old copy of Bridge.

That way you can take your time and grow the next copy of your cache with the latest version, at your own pace -- if you wish.

A window into Bridge's limits - or the corrupt cache issue, again

Well, it happened again: the dreaded “Bridge has a problem reading the cache. Purge the central cache.”

This has now happened twice on the G5 tower (my primary benchmark machine). Both times the cache had reached nearly identical size: 44gb, 364k+ items. the first time and 43gb, 352k+ items the second time.

Although a pattern seems to be emerging, it should be noted that the third time this happened was on my Macbook Pro and the size was somewhat smaller: 40gb, 298k+ items.

While we can't determine what this means with any degree of certainty, it just might indicate what the top end limits are in using Bridge.

Still. . . it pays to watch your cache levels carefully and optimize as needed (command/control + K in Bridge preferences)

Cache problem on Bridge CS4

As digital photo librarian one of my tasks is to keep Bridge on my four machines constantly indexed and updated: three have admin level and one a simple user level. I call these my benchmark machines since they are the ones by which I measure all the other users' machines in the department. Typically, they the most accurate and up-to-date for searching; they include two PCs and two Macs.

Back in July of this year, Bridge on one of my two benchmark Macs displayed the feared "purge the central cache" message:

There is no workaround and no alternative but to purge the central cache and completely reindex the machine from scratch.

Last Friday the same thing happened to my other benchmark Mac, a laptop.

And no, we don't know why this happens: the cache size remains at normal levels:44 gbs with 380k+ items (July) and 40 gbs with 306k+ items (September). No unusual activity at the server end and so far no one else in the department has experienced this problem. Of course, that last observation leads me to suspect that it does have something to do with cache size but this remains far from clear. and anyway, I've had a cache as large as 55 gbs on my laptop with no problems.

Oh and one other thing I've learned recently: Apple's Time Machine does not back up Bridge's caching system -- in fact it doesn't back up the User library's cache folder at all. Curious, eh?

"Bridge encountered a problem. . . "

The moment we've all dreaded has arrived this morning. I turned on my computer, launched Bridge and straightaway saw this on my screen:

"Bridge encountered a problem and is unable to read the cache. Please try purging the central cache in Cache Preferences to correct the situation."

Before taking any action, however, I wanted to review my cache size: (User>Library>Cache>Adobe>BridgeCS4). I soon discovered that it consumed 44 gigabytes of space and contained slightly more than 364,000 items.  Since the maximum number of items allowed is 500,000, that didn't seem too extreme. However, I did notice that there were more than 1200 cached folders in the 256 thumb folder but more than 1300 folders in the 1024 preview folder. (Even though the image library contains only a fraction of that number of folders, I use Bridge for moving files/folders around and prepping images for their eventual migration to the photo library.)

The difference between the two numbers seemed a bit odd since both folders should be the exact same size. I wonder if the cache crashed simply because of the number of folders of cached items.

Whatever the root cause, this event reminded me of the importance of tracking Bridge's cache size -- and it would probably be wise to occasionally run the Optimize Cache in Preferences as well:

Bridge>Preferences>Cache>Optimize Cache.

Have you experienced similar problems?

Previewing problems in Bridge CS4?

If you're having problems previewing images in folders you've previously indexed in Adobe Bridge CS4 try this:


1. In Bridge go to Edit>Find (Command+F)
2. Select the folder where the problem seems to occur most often (alternatively select all your image folders)
3. In the search criteria drop-downs select "keywords" and then type in the broadest keyword in your library, one that might cover all your images (such as your name, if you tag all your images that way  for example)
4. Make sure to check BOTH Include all subfolders and Include Non-indexed files
4. Click find and then walk away. Depending on how large your image library is, this might take a while (or overnight).


We've have found that using this method is one way to "clean up" any re-indexing issues that might arise in Bridge's caching process after months of re-indexing folders.


There are, of course, no guarantees so be sure to keep any eye on your caching numbers in the Library.

Adobe Bridge CS4 Previewing problem

It's been over a year since our department started using a central image library and, with only 2 or 3  minor issues, the print and web teams have experienced few problems accessing the photos using Adobe Bridge CS4. All machines have undergone both initial and repeated reindexing have produced no unexpected anomalies. Recently, however, several machines have begun to experience problems in loading previews of several recently uploaded folders.

Remember, our image library consists of a series of folders (by date), each with a varying number of images inside (but rarely over 2k or more images). Typically, once a folder of photos is cached (or "indexed) in Bridge, the program creates a separate subfolder for the thumbnails and another subfolder for the previews, all within Bridge's cache folders. (Located in the user's Library on a Mac.)

Initial indexing/caching creates all the thumbnails and previews for that one folder. Subsequent "recaching/re-indexing" only adds any additional metadata that might have been modified since the initial caching -- new images are almost never added to folders within the library.

Now, to the issue.

Beginning several weeks ago -- the timing is, unfortunately, uncertain - I began experiencing a preview loading problem on both the benchmark machines. (Two Macs, one desktop one laptop that serve as the most accurate and up-to-date sources for accessing the library.) The problem was first noticed in the search results window: previews appeared pixelated in the preview window and often remained that way. In addition, when attempting to review (or use the slideshow) feature, the images would often remain pixelated for some seconds or not load at all.

At first I thought this was isolated and temporary. But I then learned that several others were experiencing the same problem. (Only Macs, though. The two Windows machines, not overly used but one kept up-to-date, seemed fine.)

Modifying the preview generating option in the Path Bar made a short-term difference on a couple of machines, but the option was already selected on a couple of other machines exhibiting the loading problem.

When I began investigating the caching behavior of the problem machines, it soon became clear that the problem was deeper. By examining the cache folders inside of the Library cache folder structure, I could see that previews were not being generated even when the folder(s) were reindexed. In fact, I even tried purging and rebuilding the cache for several folders and watched the preview cache folder. I could easily see that not all the previews were being built and indexed.

The question now is why is this happening? The corollary is why is this happening on just a few machines? All the machines, it should be noted, are of the same vintage, and of robust features, and sharing the same OS and software.

Two concerns in using Bridge CS4 to maintain a central image library

Using Bridge CS 4 as a tool for creating, maintaining and accessing a large central image library has worked for our organization. After much testing in the summer of 2009 and continual testing and updating of our search and keywording strategies the library remains stronger than ever.

However, there are two ongoing concerns that one should be aware of: exactly what is the top end limit for the cache and what will happen when that limit is reached.

It is widely known that you can adjust the number of "items" in Bridge's cache preferences from 10k to 500k. But exactly what does Adobe mean by an "item"?

Elsewhere they use the word "record" but generally the word item seems to be most favored. For example, is a RAW image file and its sidecar metadata file considered two items? Is each thumbnail and each preview a separate item?

If the answer is yes to both questions, then it is safe to assume that one camera RAW image could in fact be read by Bridge as four distinct items. It wouldn't take Bridge long to reach the maximum threshold of 500k.

Second, exactly what happens when Bridge reaches its maximum number of items?

According to Adobe's user guide (May 2009) for Bridge and Version Cue, "If the cache is near the defined limit (500,000 records) or the volume that contains the cache is too full, older cached items are removed when you exit Adobe Bridge."

Here, again, we are in murky waters. Note the use of both the maximum number of records or if "the cache is too full." Exactly what does the latter mean and how does it differ from the former?

I have yet to discover the answers to either question -- perhaps none exist, at least not an answer that would cover any and all possibilities.

Any ideas, comments or questions, please feel free to contact me: steve.soper@jwu.edu