Re: memory cache not written out to disk on shutdown?

Stuart Maclean Wed, 19 Aug 2009 13:59:55 -0700

Hi Jeffrey, this appears to work. I se t the disk usage pattern toUPDATE, and see the .data file growing on disk while the app runs. Ialso removed any explicit shutdown calls from my code. When I exit, Isee the .key file on disk grow, so an internal shutdown listener issaving the keys, as Aaron suggested.

So maybe this is the config I need for my situation. As long as thekey and data files are in synch I guess I am good to go.


Thanks again

Stuart

On Aug 19, 2009, at 1:42 PM, Jeffrey Kesselman wrote:

as someone else mentioned, if your concerned about retaining yourcacheddata you really shouldn't be waiting til shut down to try to saveit. UseUPDATE and save it as you go, which is what i do in my remotes andit works

fine.


On Wed, Aug 19, 2009 at 4:27 PM, Stuart Maclean
<stu...@apl.washington.edu>wrote:

Well, I print out some debug in my VM shutdown listener after thecall toCCF.shutdown and the debug appears, so I assume the shutdown callis firing.

I'll install the 1.3.3.5-RC version. Do I use the existing pom doyou

know, or copy the pom to a new one and tweak?

Stuart


On Aug 19, 2009, at 1:08 PM, Aaron Smuts wrote:

You can download the latest temp build and put it in your local maven

repo. You aren't forced to only use a remote repo with maven. Noone woulduse maven otherwise. You wouldn't be able to use your ownlibraries. . . .


Running in INFO log level is fine.

"Disk cache not shutdown properly, shutting down now." Shouldn'tshow upif shutdown was called. That's only called if the vm shutdownlistenerdetects the shutdown. That won't flush memory, it will merelywrite the keyfile to disk. To get the memory contents to disk, you have to doan orderly

shutdown.  Are you sure the listener works?

Can you past in the logs after shutdown is called.

You can also configure the region to use theDiskUsagePatternName=UPDATE.


Aaron

--- On Wed, 8/19/09, Stuart Maclean <stu...@apl.washington.edu>wrote:


From: Stuart Maclean <stu...@apl.washington.edu>

Subject: Re: memory cache not written out to disk on shutdown?
To: "JCS Users List" <jcs-users@jakarta.apache.org>
Date: Wednesday, August 19, 2009, 12:48 PM
Hi Aaron,

I just configured a log4j logger, appender for
org.apache.jcs, set to DEBUG,and I get a ton of output in
the log.  Nothing looks awry, one WARN though.

2009-08-19 12:39:54,598 13711 WARN   -
Region [OpenStreetMaps] Disk cache not shutdown properly,
shutting down now.
2009-08-19 12:39:54,598 13711 INFO   - In
DISPOSE, [OpenStreetMaps] fromRemote [false]
Re

This issue is driving me mad, it seems random.  I'll
clear the cache dir, run the app, exit and inspect the cache
dir and both /key and .data files will have size 0.
Then I'll run again and things appear to start to work, and
the disk cache builds up.  It's as if there is some
race condition in the shutdown process.  yes, I am
calling CCF.getInstance().shutdown() in my own VM shutdown
listener.  Is the jcs shutdown process synchronous, or
does it spawn a new thread, which might be been abandoned by
my VM?

I am using jcs 1.3 on jdk 1.6.0_14 on  Mac 10.5.
I am using maven2 for build, so not sure if I can try the
latest jcs build?

Any help appreciated.

Stuart

On Aug 19, 2009, at 12:25 PM, Aaron Smuts wrote:

What version are you using?  (I recommend the

latest temp build.)


Try shutting down in an orderly fashion.  Call

shutdown on the CompositeCacheManager.  In any case,
the disk cache registers a vm shutdown listener.  It
should write the data.


Are there errors in the log?

Do you see any .data file?  If not, there may be

a configuration or a file permission problem.  Check
the logs.  Set the memory size to 0 and see if the data
goes to disk during normal usage.


Aaron

--- On Wed, 8/19/09, Stuart Maclean <stu...@apl.washington.edu>

wrote:


From: Stuart Maclean <stu...@apl.washington.edu>

Subject: memory cache not written out to disk on

shutdown?

To: jcs-us...@jakartaapache.org


Date: Wednesday, August 19, 2009, 12:04 PM
Hi all, I am trying to use JCS in a
mapping application.  I have a Swing map

tool, which

retrieves and displays map tile images from eg

openstreetmap.org.  Logically my cache

objects are

Images, though I am converting to and from int[]

for

serialization.  My cache keys are a string

encoding of

the map tile components z,y,x, e.g z-y-x.


In my cache.ccf, I am specifying properties just

for

default regions.  I am right in assuming that

my named

regions in my code 'inherit' their configuration

from the

defaults?  Is it true also that if I use two

regions,

R1 and R2, that EACH region gets its own 10

objects

(MaxObjects) or is 10 the total number of

in-memory cached

objects?


What I want to happen is this.  When cache

empty, go

to map tile server and get tiles.  Store to

JCS cache.

Mainatin say 50 in memory for each tile 'layer'

(where a

layer maps to a tile set from one map

server).  When my

app requires the 51st image, flush LRU to disk

cache. When

my app exits, serialize the entire memory cache to

disk,

effectively using the cache as a persistence

engine.

When restart my app, get Images from local disk

before going

to remote map server.


Alas, when I call shutdown (from a VM shutdown

listener,is

this the problem???) my .key and .data files on

disk never

seem to be updated  It's as though the in

memory cache

is never 'flushed' to disk?  Should it be?


I seem to be missing something here?  Any

help

appreciated.
Stuart

My cache.ccf is here...

jcs.default=DC
jcs.default.cacheattributes=org.apache.jcs.engine.CompositeCacheAttributes

jcsdefault.cacheattributes.MaxObjects=10
jcs.default.cacheattributes.MemoryCacheName=org.apache.jcsengine.memory.lru.LRUMemoryCache

jcs.default.elementattributes.IsEternal=true

jcs.default.elementattributes.MaxLifeSeconds=1000000

jcs.default.elementattributes.IdleTime=1800

jcs.default.elementattributes.IsSpool=true
jcs.default.elementattributes.IsRemote=true
jcs.default.elementattributes.IsLateral=true
jcs.auxiliary.DC=org.apache.jcs.auxiliary.disk.indexed.IndexedDiskCacheFactory

jcs.auxiliary.DC.attributes=org.apache.jcs.auxiliary.disk.indexed.IndexedDiskCacheAttributes

jcs.auxiliary.DC.attributes.DiskPath=${user.home}/.sgDesktop/map/cache3

jcs.auxiliary.DC.attributes.MaxKeySize=100000


jcsauxiliary.DC.attributes.MaxPurgatorySize=100000

#jcs.auxiliary.DC..attributes.ShutdownSpoolTimeLimit=60


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Re: memory cache not written out to disk on shutdown?

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