How good is DSP caching?

I am trying to understand how good is DSP caching and what functionality does it exactly provide behind the scene.
It is very easy to check for exact repetition of a query in given time frame and returning older results from cache. I am wondering whether DSP does any of the advance stuff like following:
1. Are new queries compared against old queries in cache to check whether data retreived by new query will be a subset of data retrieved earlier? If it does so, it could just query the data it already has in cache and return result set.
2. If DSP does comparison as mentioned in 1, does it do comparisons individually with original queries in cache or with a unified version of all queries in its cache?

DSP caches only exact function calls - same function, same parameters, same user. This can be a top-level function, or a function called within another function.
Enable DSP caching only if you have an exact case that will benefit. I would recommend to only cache slow webservices - nothing else unless you really know what you are doing.

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How to trigger DSP cache invalidation and reload?

We have a scheduled job to update the database nightly. I used DSP caching to increase performance since the data only changes during the nightly updates.
Does anyone know how can I trigger the DSP cache invalidation and reload the updated data to DSP cache once the data loading is completed on the database server? (The database is hosted on a different server than DSP.)
Thanks in advance!
Nav

On this page
http://e-docs.bea.com/aldsp/docs25/appdev/ejbclt.html
Bypassing the Data Cache When Using the Mediator API
Data retrieved by data service functions can be cached for quick access. This is known as a data caching. (See Configuring the Query Results Cache, in the DSP Administration Guide for details.) Assuming the data changes infrequently, it's likely that you'll want to use the cache capability.
You can bypass the data cache by passing the GET_CURRENT_DATA attribute within a function call, as shown in Listing 3-7. GET_CURRENT_DATA returns a Boolean value. As a by-product, the cache is also refreshed.
Listing 3-7 Cache Bypass Example When Using Mediator API
dataServices.customermanagement.CustomerProfile customerProfileDS =
customerDS=dataServices.customermanagement.CustomerProfile.getInstance(ctx,appName);RequestConfig
config = new
RequestConfig();attr.enableFeature(RequestConfig.GET_CURRENT_DATA);CustomerProfileDocument
customerProfileDoc customerPlofileDS.CustomerProfile(params,config);

How do I empty "cache"?

How do I empty "cache"?

The best way to do this is simply to boot into Safe Mode.
Here's what to do:
1. Restart your computer
2. Just as you hear the chime sound and see a white screen on startup, hold down the shift key
3. You will see a progress bar as your computer boots into safe mode and clears your cache.
4. Simply restart normally, and your cache is clear.
Good luck!

How good is the audio jack?

In the past I've connected my iPod to my stereo using a mini to RCA adapter. It gave me a weak signal (even with the volume turned all the way up). How good is the Mac Mini's audio when plugging into a stereo? Thanks.

Optical out to a DAC supports 24-bit (and even 32-bit on the new mini, whatever that is for, I guess DSP). It shares the analogue headphone jack out, but when you put a mini Toslink in it, you get the light out.
You can also use USB out or use a USB/coax converter (which I am messing around with). Others have told me that the USB/coax converter is better because it externally clocks the signal, but I cannot hear any difference between that and the optical out. Optical goes up to 96kHz sampling frequency. To get higher, you need the USB/coax adapter.
The NOVA that I have, linked to above, supports 16-bit output from USB and 24-bit output from optical toslink and coax. I think the USB limitation might be imposed by the software in the DAC, however, not at the mac end.

How much data canbe cache in SGA

Hai everybody,
my company using Oracle 11g 11.2.0.1.0 - Production database, my os is RHEL 5.5 ,my server's physical memory is 30.9 GB ( cat /proc/meminfo ) ie the SGA size [ (30.9*40/100)=12.5 GB ] so i use 12.5GB SGA size for one instance, we need to cache some data for our application performance how much data can cache in SGA based on 12.5 GB or how to calculate how much data can cache in SGA without any performance degradation.
Regards Benk

Aman has it right. WHY?
the keep pool, alter table cache, etc - I would not be doing ANY of these without a good reason.
Often times, people think that forcing a table to stay in the cache is a good idea. It rarely is. If you want things in the cache, use them. If they are used, they will naturally have their blocks cached. If you don't use them, they can get flushed out. But if you don't use them, why do you want them using memory that could better be used by other things?
My advice: don't try to second-guess Oracle's memory management and caching strategy. If you think you have a reason to, post it here and we can help you (or debunk your reason). Based on the fact that you've apparently calculated the SGA using that silly, meaningless "rule" that says give it 40% of your total RAM, I'd guess that you are looking around for a magic bullet, and you don't actually have a problem to solve.
John

How to create a cache for JPA Entities using an EJB

Hello everybody! I have recently got started with JPA 2.0 (I use eclipseLink) and EJB 3.1 and have a problem to figure out how to best implement a cache for my JPA Entities using an EJB.
In the following I try to describe my problem.. I know it is a bit verbose, but hope somebody will help me.. (I highlighted in bold the core of my problem, in case you want to first decide if you can/want help and in the case spend another couple of minutes to understand the domain)
I have the following JPA Entities:
@Entity Genre{
private String name;
@OneToMany(mappedBy = "genre", cascade={CascadeType.MERGE, CascadeType.PERSIST})
private Collection<Novel> novels;
@Entity
class Novel{
@ManyToOne(cascade={CascadeType.MERGE, CascadeType.PERSIST})
private Genre genre;
private String titleUnique;
@OneToMany(mappedBy="novel", cascade={CascadeType.MERGE, CascadeType.PERSIST})
private Collection<NovelEdition> editions;
@Entity
class NovelEdition{
private String publisherNameUnique;
private String year;
@ManyToOne(optional=false, cascade={CascadeType.PERSIST, CascadeType.MERGE})
private Novel novel;
@ManyToOne(optional=false, cascade={CascadeType.MERGE, CascadeType.PERSIST})
private Catalog appearsInCatalog;
@Entity
class Catalog{
private String name;
@OneToMany(mappedBy = "appearsInCatalog", cascade = {CascadeType.MERGE, CascadeType.PERSIST})
private Collection<NovelEdition> novelsInCatalog;
The idea is to have several Novels, belonging each to a specific Genre, for which can exist more than an edition (different publisher, year, etc). For semplicity a NovelEdition can belong to just one Catalog, being such a Catalog represented by such a text file:
FILE 1:
Catalog: Name Of Catalog 1
"Title of Novel 1", "Genre1 name","Publisher1 Name", 2009
"Title of Novel 2", "Genre1 name","Pulisher2 Name", 2010
FILE 2:
Catalog: Name Of Catalog 2
"Title of Novel 1", "Genre1 name","Publisher2 Name", 2011
"Title of Novel 2", "Genre1 name","Pulisher1 Name", 2011
Each entity has associated a Stateless EJB that acts as a DAO, using a Transaction Scoped EntityManager. For example:
@Stateless
public class NovelDAO extends AbstractDAO<Novel> {
@PersistenceContext(unitName = "XXX")
private EntityManager em;
protected EntityManager getEntityManager() {
return em;
public NovelDAO() {
super(Novel.class);
//NovelDAO Specific methods
I am interested at when the catalog files are parsed and the corresponding entities are built (I usually read a whole batch of Catalogs at a time).
Being the parsing a String-driven procedure, I don't want to repeat actions like novelDAO.getByName("Title of Novel 1") so I would like to use a centralized cache for mappings of type String-Identifier->Entity object.
Currently I use +3 Objects+:
1) The file parser, which does something like:
final CatalogBuilder catalogBuilder = //JNDI Lookup
//for each file:
String catalogName = parseCatalogName(file);
catalogBuilder.setCatalogName(catalogName);
//For each novel edition
String title= parseNovelTitle();
String genre= parseGenre();
catalogBuilder.addNovelEdition(title, genre, publisher, year);
//End foreach
catalogBuilder.build();
2) The CatalogBuilder is a Stateful EJB which uses the Cache and gets re-initialized every time a new Catalog file is parsed and gets "removed" after a catalog is persisted.
@Stateful
public class CatalogBuilder {
@PersistenceContext(unitName = "XXX", type = PersistenceContextType.EXTENDED)
private EntityManager em;
@EJB
private Cache cache;
private Catalog catalog;
@PostConstruct
public void initialize() {
catalog = new Catalog();
catalog.setNovelsInCatalog(new ArrayList<NovelEdition>());
public void addNovelEdition(String title, String genreStr, String publisher, String year){
Genre genre = cache.findGenreCreateIfAbsent(genreStr);//##
Novel novel = cache.findNovelCreateIfAbsent(title, genre);//##
NovelEdition novEd = new NovelEdition();
novEd.setNovel(novel);
//novEd.set publisher year catalog
catalog.getNovelsInCatalog().add();
public void setCatalogName(String name) {
catalog.setName(name);
@Remove
public void build(){
em.merge(catalog);
3) Finally, the problematic bean: Cache. For CatalogBuilder I used an EXTENDED persistence context (which I need as the Parser executes several succesive transactions) together with a Stateful EJB; but in this case I am not really sure what I need. In fact, the cache:
Should stay in memory until the parser is finished with its job, but not longer (should not be a singleton) as the parsing is just a very particular activity which happens rarely.
Should keep all of the entities in context, and should return managed entities form mehtods marked with ##, otherwise the attempt to persist the catalog should fail (duplicated INSERTs)..
Should use the same persistence context as the CatalogBuilder.
What I have now is :
@Stateful
public class Cache {
@PersistenceContext(unitName = "XXX", type = PersistenceContextType.EXTENDED)
private EntityManager em;
@EJB
private sessionbean.GenreDAO genreDAO;
//DAOs for other cached entities
Map<String, Genre> genreName2Object=new TreeMap<String, Genre>();
@PostConstruct
public void initialize(){
for (Genre g: genreDAO.findAll()) {
genreName2Object.put(g.getName(), em.merge(g));
public Genre findGenreCreateIfAbsent(String genreName){
if (genreName2Object.containsKey(genreName){
return genreName2Object.get(genreName);
Genre g = new Genre();
g.setName();
g.setNovels(new ArrayList<Novel>());
genreDAO.persist(t);
genreName2Object.put(t.getIdentifier(), em.merge(t));
return t;
But honestly I couldn't find a solution which satisfies these 3 points at the same time. For example, using another stateful bean with an extended persistence context (PC) would work for the 1st parsed file, but I have no idea what should happen from the 2nd file on.. Indeed, for the 1st file the PC will be created and propagated from CatalogBuilder to Cache, which will then use the same PC. But after build() returns, the PC of CatalogBuilder should (I guess) be removed and re-created during the succesive parsing, although the PC of Cache should stay "alive": shouldn't in this case an exception being thrown? Another problem is what to do when the Cache bean is passivated. Currently I get the exception:
"passivateEJB(), Exception caught ->
java.io.IOException: java.io.IOException
at com.sun.ejb.base.io.IOUtils.serializeObject(IOUtils.java:101)
at com.sun.ejb.containers.util.cache.LruSessionCache.saveStateToStore(LruSessionCache.java:501)"
Hence, I have no Idea how to implement my cache.. Can you please tell me how would you solve the problem?
Many thanks!
Bye

Hi Chris,
thanks for your reply!
I've tried to add the following into persistence.xml (although I've read that eclipseLink uses L2 cache by default..):
<shared-cache-mode>ALL</shared-cache-mode>
Then I replaced the Cache bean with a stateless bean which has methods like
Genre findGenreCreateIfAbsent(String genreName){
Genre genre = genreDAO.findByName(genreName);
if (genre!=null){
return genre;
genre = //Build new genre object
genreDAO.persist(genre);
return genre;
As far as I undestood, the shared cache should automatically store the genre and avoid querying the DB multiple times for the same genre, but unfortunately this is not the case: if I use a FINE logging level, I see really a lot of SELECT queries, which I didn't see with my "home made" Cache...
I am really confused.. :(
Thanks again for helping + bye

How do I clear cache and cookies on my ipad

How do I clear cache and cookies on my ipad? I was told to do this when I was trying to download ebooks to ibooks and kindle

Settings/safari/clear history;clear cookies and data

How do I delete caches in Lion and which can I delete?

How do I delete caches in Lion and which ones can be deleted?

you can delete all of them, they will be recreated as soon as the app opens again.
Clearing Local Caches
quit all open apps
open Finder press "shift+command+G" and type ~/Library/Caches
Drag all files and folders to the trash
Enter login password when prompted
Reboot
your system may seem slower after reboot, this is because the caches are being rebuilt.
Clearing Application Caches
quit all open apps
open Finder Press "shift+command+G" and type /Library/Caches
Drag all files and folders to the trash
Reboot

How good is password protection in Preview App

I want to open some PDF's in Preview, do a Print command, then when that opens select PDF and then Save as PDF. When that window opens, I will then click on Security Options and enter a password that will be required to open the doc. I need to then email these docs to a person on a PC. They have Adobe Acrobat. I've dropped one of these docs on my Windows 7 Virtual Machine. When it opens using Adobe Acrobat it asks for the password and when entered correctly, the doc opens.
So far so good. But how good is the password protection??? I've been told that Office has had good encryption (128 bit AES) since Office 2007. But what about Preview on the Mac being opened by Acrobat on a PC??? Bad?? Good??
There are reasons why it is not reasonable to try to drop a large number of pdfs into Microsoft Word so I'm leaning instead toward just protecting the Preview PDF versions.
Thoughts???
thanks... bob..

As I tell people in the Reader and Acrobat forums, if someone wants to "crack" a PDF badly enough, nothing (including DRM) will prevent them.
AFAIK, Preview's encrytpion is as good as Acrobat's.
The password rules are the same. Longer and more cryptic = better protection. 12 characters is better than 8... 16 is better than 12... Upper & lower case, numerals and special characters.

IPAD 6.0 (MD519C/A) wifi,cellular - how good is this model?

I would like to buy Apple iPad with Retina display (MD519C/A), 16GB, WiFi, Cellular 4G, White from Staples.ca. I would like to know if anyone has used this model and how good is this. Also, whether it's unlocked or not? I want to send the ipad to Bangladesh and the customer representative at Staples was not sure whether that is unlocked or not. I would like to know if it would work there.
I have pasted the URL for this ipad. Thank you.
http://www.staples.ca/en/Apple-iPad-with-Retina-display-MD519C-A-16GB-WiFi-Cellu lar-4G-White/product_105913_2-CA_1_20001

Without checking myself, just be aware that the iPad OS generally only provides error signals that are relevant. It wouldn't seem relevant to report on a missing SIM with Cellular turned off, and I'd therefore expect that you wouldn't see that message after having done so.
Don't turn on Airplane Mode, however (that's what's shown by the "little airplace icon") as that also shuts down your wifi.
And yes, with Cellular off it just says "iPad" there on the status bar, exactly as described in your User's Guide and other locations.

How good is the Collections.shuffle() method?

Hello
I have an ArrayList which I want to bootstrap from. I did not find any method to randomly select an entry from the ArrayList, so I use the shuffle method first, and then get the first entry (which should be random after each shuffle). However, I do get some strange results from this. On average the numbers gotten when I sample small series is lower then the ones I get sampling longer series. There is no aspect with the data that should imply such behavoiur. Does anyone know how good my way of sampling is (using shuffle), and if the shuffle method really is a good way to randomize?
Regards
JT

I think the API docs probably give the best answer to this question. Notice the word "approximately" In the shuffle(List) method. Also note that shuffle.(List, Random) depends on how "good" Random is.
I guess you'd have to construct some form of test to see if either shuffle was good enough for your requirements.
Cheers
DB

How good is the 3G arial on the iPad?

How good is the 3G arial on the iPad? For example is it better than the iPhone 4 one?

I'm using the IGP on 2 networked pc's and to be honest have had no problems with it. Runs all my games at ease inc the network games, (some are very power hungry too). Ok not as fast as the latest all singing cards but costs you nothing. You can always stick another card in if you get problems. One thing though, gotta make sure you make use of the Dual channel memory, this really speeds things up with the IGP in use.

How good is the new Adobe Reader IOS for fillable forms and interactive pdfs?

At last adobe reader for ios has been updated so now fillable forms can be completed on ipad/iphone but how good is it?
I've tested a form and reset form/print form and save as buttons do not seem to work.
Form submit seems ok, just wondered what others thought?
Also the new Adobe Reader IOS is now able to display interactive pdfs with buttons such as go to next page etc yet page transitions do not work? Again whats everyone elses opinion on the reader ios update?

My preliminary experience is that Reader does better with forms than with interactivity.
I've written a couple postings on InDesignSecrets.com about PDF readers for tablets. Here's the latest one:
Finding the Best Tablet PDF Reader
You should also check out PDF Expert (US $9.99) which handles interactivity better than Reader if that is important to you.

24bit interface into 16bit GB - how good is the conversion?

I have a Focusrite Saffire LE interface which I'm planning to use for recording into GarageBand. It's a 24-bit interface, but as GB only allows 16-bit recording some conversion must take place...
Do you know how good the conversion is?
Is it a proper conversion with dithering or are the least significant bits just truncated?
Mac Mini + G3 Mac OS X (10.4.9)
Mac Mini + G3 Mac OS X (10.4.6)

hey there alfredo,
what software will you be using? GB3 & earlier will only support 16/44.1, CD quality. the hardware interface will also come into play-what will you be using?
for example-i have a MOTU 828 that does 24/96, but even w/ GB3 it dithers down & goes in as 16/44.1; but w/ MOTU DP4 i can use the 24/96 setting. Logic Pro will support 24/96 & ProTools HD w/ dedicated hardware will support 24/192. iTunes will support 16/44.1. generally the higher bit & sampling rates are for recording, no matter what it goes in as when burning to an audio CD it becomes 16/44.1 the industry standard.

Lost iPhone - how good is the PIN protection?

My iPhone was recently stolen and I'm concerned about the data that I had on it. The phone was PIN protected. How good is this PIN protection? Is it possible someone can recover the data from the phone without knowing the PIN?
Given in the UK if a phone is stolen its completely useless since the IMEI is blocked on all networks, I assume that it can still be used in an ipod touch type fashion? Is that so?

In regards to the iPhone's passode lock feature, if someone knows what they are doing and has the proper tools/utility, an assigned passcode lock can be bypassed - just as if someone wants to break in to your house or vehicle that is locked - where there is a will, there is a way.
Doubtful whoever stole your iPhone is interested in your data. If you had the erase data feature enabled, which completely erases the iPhone after 10 failed passcode attempts, you are covered there.

How good is DSP caching?

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