Speed of random key access

hi,
we have a bdb with around 1 million entries in it. keys are small (~20 bytes), values are large (~2k). i was just wondering if there are any strategies for optimizing random key access. basically, we run operations where we end up with a collection of keys (say 20), which we then iterate through, retrieving each entry. is there any strategy for optimizing this? (e.g. sorting keys in the same order as the database.)
thanks,
-james

Hi James,
Sorting keys certainly won't hurt, but unless there's a good chance of locality of some of the keys you'll still hit random spots on the disk. If keys are sorted in insertion order, then it's likely that there will be locality. Alternatively, if you can sort to insertion order (if insertion order != key order), that might work too. Again, it depends on the proximity of the keys in your 20-key set.
But a more fundamental question is whether you can just allocate a large enough cache to fit the entire database in memory. You can load the entire database using Database.preload(); If you can't increase the cache size, then you could try cleaning the log to a smaller size. This increases the likelihood of hits in the file system cache. But cleaning to a higher minUtilization is also expensive.
Regards,
Charles Lamb

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Things I have tried (according to research via google):
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Windows 7 Home premium 64 bit.
AMD phenom II X4 945 Processor
8GB RAM
AMD RADEON HD 5450
Keyboard: Steelseries Shift
Mouse: Razer Deathadder
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Because you mentioned in the sidenote/story that you adjusted the settings for your Razer Deathadder and had success for a few minutes, have you thought to, perhaps, uninstall the software to see if the issue goes away permanently? I don't know of any reason that it would have conflicts with anything else on your computer, but it might be an interesting troubleshooting step to try. Other than that suggestion, I wouldn't know where to go with this...
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I work on behalf of HP.

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Simulate that i hold an random Key.

Hey,
i just oponend an discussion for an long time ago and marked those as solved, but ihe advice from User called Melophage doesn't helps.
"Hey Guys,
i just want to generate an Caps Lock Function for my Option Key, cause of my handicap i couldn't hold this Key anytime.
Any Suggestions or advices to fix my problem as soon as possible.
Thanks in advance.
n1mare.!
n1mare,
KeyRemap4MacBook will allow you to set either Option key (or both Option keys) to act as a Caps Lock."
Hi Melophage,
i just need to correct my reply. It doesn't works. I don't want to act with my option keys as Caps lock. I just want to simulate, that i hold those Keys. (for example Shift_L & Option_R)
Hopefully my explanations are understandable and you could help soon as possible.
Many Thanks.
n1mare.
Message was edited by: n1mare

n1mare,
if you still have KeyRemap4MacBook installed, you can set up a “Control Lock” function through e.g. checking the “▼ Change Control_L Key (Left Control) → Control_L to Sticky Control_L” checkbox — this would turn the left Control key into a Control Lock key.
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Hi,
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Roger Lu
TechNet Community Support

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Modify to not use a random key

Can anyone help me modify this program so it doesn't use a random key? I want to decrypt the password in another program, so I don't want to have to read a key file.
I've seen some forums posts doing something similar, but so far I haven't been able to successfully change mine. I don't think it would take much.
Anyway, any help is appreciated.
James
Here's the Encrypt code:
import java.io.*;
import java.security.*;
import javax.crypto.*;
import sun.misc.*;
public class EncryptPassword
     public static void main(String args[]) throws Exception
          if(args.length<1)
               System.out.println("Usage : EncryptPassword text");
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          try
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               key=(Key)in.readObject();
               in.close();
          }      catch(FileNotFoundException fnfe)
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          String base64 = encoder.encode(raw);
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Decrypt code:
import java.io.*;
import java.security.*;
import javax.crypto.*;
import sun.misc.*;
public class DecryptPassword
     public static void main(String args[]) throws Exception
          if(args.length<1)
               System.out.println("Usage : DecryptPassword text");
               return;
          Security.addProvider(new com.sun.crypto.provider.SunJCE());
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          try
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               key=(Key)in.readObject();
               in.close();
          }      catch(FileNotFoundException fnfe)
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[\code]

I get errors when I'm trying to use the sample code you sent. What else do I need to import to use DESKeySpec? I tried import javax.crypto.spec.DESKeySpec.*;
When I try to compile I get this:
C:\Temp\Java>javac EncryptPassword.java
EncryptPassword.java:41: cannot resolve symbol
symbol : class DESKeySpec
location: class EncryptPassword
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
EncryptPassword.java:41: cannot resolve symbol
symbol : class DESKeySpec
location: class EncryptPassword
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
EncryptPassword.java:41: possible loss of precision
found : int
required: byte
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
EncryptPassword.java:41: possible loss of precision
found : int
required: byte
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
EncryptPassword.java:41: possible loss of precision
found : int
required: byte
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
EncryptPassword.java:41: possible loss of precision
found : int
required: byte
DESKeySpec ks = new DESKeySpec(new byte[] { 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF });
^
6 errors
Thanks,
James

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Reading a record by key access.

Hi Gurus,
In 'read table' for reading a record by key access they have used 'comparing' , 'transporting' , 'assigning'.
Can you please explain me what exactly the above will happen with an clear example.
Thanks,
Prabu S.

mostly you wont need these
but still: from documentation:
READ TABLE - transport_options
Syntax
... [COMPARING { {comp1 comp2 ...}|{ALL FIELDS}|{NO FIELDS} }]
[TRANSPORTING { {comp1 comp2 ...}|{ALL FIELDS} }] ... .
Effect:
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are assigned to the corresponding components of the work area (or their subareas). If ALL FIELDS is specified, all the
components are assigned.
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WHY WON'T STICKY KEYS ACCESSABILITY WORK ON SAFARI/

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RANDY

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I don;t know what the @#$ is going on with this device, but for example:
user A creates a folder in their area(under a share with RW rights)
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Key Access NFe J1B3N - SQVI

Dear experts
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Secret and random key

Which algorithms use a secret key and a random key?
Which of these are implemented (or at last con be implemented) in J2SE and J2ME?

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Which of these are implemented (or at last con be
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import java.util.Enumeration;
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Speed of random key access

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