Getting TIME ELAPSED on date
Posted: January 16, 2012 Filed under: Oracle Leave a comment »select created,updated,
trunc((86400*(updated-created ))/60)
from MYTABLE where and trunc((86400*(updated-created ))/60)>10
Generate oAuth key in ..
Posted: December 14, 2011 Filed under: Uncategorized Leave a comment »Java
public String computeHmac(String baseString, String key) throws NoSuchAlgorithmException, InvalidKeyException, IllegalStateException, UnsupportedEncodingException { Mac mac = Mac.getInstance("HmacSHA1"); SecretKeySpec secret = new SecretKeySpec(key.getBytes(), mac.getAlgorithm()); mac.init(secret); byte[] digest = mac.doFinal(baseString.getBytes()); return Base64.encode(digest); }orMessageDigest digest = MessageDigest.getInstance("SHA-1"); digest.reset(); byte[] hash = digest.digest(body.getBytes("UTF-8")); String encodedHash = Base64.encode(hash);
MySQL 99.9% CPU , 1.4%Memory , help ….
Posted: October 25, 2011 Filed under: Uncategorized Leave a comment »Before I jumped into my findings , here I share my problem of my SMS system
- > 200 request per minutes
- 20 persistent connection <- I used OJB framework, now it is in the ATTIC
- 99.9% MySQL CPU
- 150Kb/s traffic to MySQL
- I panic
- MySQL 5.1.35 running on Redhat Linux Release 9 (Shrike)
- No my.cnf , running on default installation
MySQL – no my.cnf when installing in Linux
Posted: October 25, 2011 Filed under: MySQL Leave a comment »I just found out here on how to have the file. By default, no my.cnf will be created during installation. Therefore some SERVER VARIABLES may be set up during session initialized.
Before creating the file, make sure check if any my.cnf exists in the system. If we want to overide existing my.cnf which we don’t know which one is using, simply create my.cnf in /etc/my.cnf
Tomcat 5.5 keeps on reloading context and cause logs full
Posted: June 13, 2011 Filed under: Uncategorized Leave a comment »this new things i found that Tomcat keeps on reloading context, still cannot find the answer
Generating SSL key in Mac
Posted: May 19, 2011 Filed under: Linux, Shell Command Leave a comment »This info I found from
http://superuser.com/questions/73979/how-to-easily-create-a-ssl-certificate-and-configure-it-in-apache2-in-mac-os-x
Question:
I’d like to use my Mac OS X with https for local development tests. How can I easily make Apache2 respond to ssl, just for test proposes – I don’t want a real certificate, just a fake to make local https work ?
Answer:
Generating the private key:
output:
enter a passphrase for your private key.
Generating the CSR (certificate signing request):
It will request details like this:
State or Province Name (full name) [Berkshire]:
Locality Name (eg, city) [Newbury]:
Organization Name (eg, company) [My Company Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server’s hostname) []:
Email Address []:
Please enter the following ‘extra’ attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
it’s fairly straightforward, the common name is your server’s hostname as it says in brackets.
Generating the self signed certificate:
Configuring SSL in httpd.conf for Apache:
SSLCertificateFile /path/to/generated/server.crt
SSLCertificateKeyFile /path/to/generated/server.key
(replace path appropriately with the path to your certificate and key)
Restart Apache:
Apache will ask you for the passphrase to your key. If you think you will be shutting the server down a lot, you may want to remove the passphrase from the key so you can avoid entering it each time. If not, don’t worry about it. If so, complete this step after step 2 (Generating the CSR):
openssl rsa -in server.key.copy -out server.key
Oracle high CPU usage
Posted: May 7, 2011 Filed under: Oracle Leave a comment »Below is sql statement to check CPU usage on database. You can login with any DB user and run it.
select nvl(ss.USERNAME,'ORACLE PROC') username, se.SID,ss.logon_time, VALUE cpu_usage,osuser from v$session ss, v$sesstat se, v$statname sn where se.STATISTIC# = sn.STATISTIC# and NAME like '%CPU used by this session%' and se.SID = ss.SID order by VALUE desc ------------------ SELECT s.sid, p.spid "OS Pid", s.module, s.process, s.schemaname "Schema", s.username "Username", s.osuser "OS User", s.program "Program", substr(a.sql_text,1,550) "SQL Text" FROM v$session s, v$sqlarea a, v$process p WHERE s.sql_hash_value = a.hash_value (+) AND s.sql_address = a.address (+) AND s.paddr = p.addr and nvl(a.sql_text,'-')!='-' --and s.sid in (418) and p.spid in (<your OS process id on the db server by running command prstat>)
Fastest to way to calculate SMS text length and divided message
Posted: April 5, 2011 Filed under: Uncategorized Leave a comment »(length / 160) + (length%160 > 0 ? 1 : 0)
Manipulating BIG file in JAVA
Posted: March 30, 2011 Filed under: JAVA Leave a comment »This was discussed back in 2002 during the early of Java, reading and writing big files has been an issue since and til now. Found this article at
http://www.techrepublic.com/article/handling-large-data-files-efficiently-with-java/1046714 /** * Reads a file storing intermediate data into a list. Fast method. * @param file the file to be read * @return a file data */ public byte[] read2list(String file) throws Exception { InputStream in = null; byte[] buf = null; // output buffer int bufLen = 20000*1024; try{ in = new BufferedInputStream(new FileInputStream(file)); buf = new byte[bufLen]; byte[] tmp = null; int len = 0; List data = new ArrayList(24); // keeps peaces of data while((len = in.read(buf,0,bufLen)) != -1){ tmp = new byte[len]; System.arraycopy(buf,0,tmp,0,len); // still need to do copy data.add(tmp); } /* This part os optional. This method could return a List data for further processing, etc. */ len = 0; if (data.size() == 1) return (byte[]) data.get(0); for (int i=0;i<data.size();i++) len += ((byte[]) data.get(i)).length; buf = new byte[len]; // final output buffer len = 0; for (int i=0;i<data.size();i++){ // fill with data tmp = (byte[]) data.get(i); System.arraycopy(tmp,0,buf,len,tmp.length); len += tmp.length; } }finally{ if (in != null) try{ in.close();}catch (Exception e){} } return buf; }
How to read very BIG text files in Java
Posted: March 17, 2011 Filed under: JAVA Leave a comment »I found this on
http://code.hammerpig.com/how-to-read-really-large-files-in-java.html
import java.util.*;
import java.io.*;
public class BigFile implements Iterable<String>
{
private BufferedReader _reader;
public BigFile(String filePath) throws Exception
{
_reader = new BufferedReader(new FileReader(filePath));
}
public void Close()
{
try
{
_reader.close();
}
catch (Exception ex) {}
}
public Iterator<String> iterator()
{
return new FileIterator();
}
private class FileIterator implements Iterator<String>
{
private String _currentLine;
public boolean hasNext()
{
try
{
_currentLine = _reader.readLine();
}
catch (Exception ex)
{
_currentLine = null;
ex.printStackTrace();
}
return _currentLine != null;
}
public String next()
{
return _currentLine;
}
public void remove()
{
}
}
}
BigFile file = new BigFile("C:\Temp\BigFile.txt");
for (String line : file)
System.out.println(line)