Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Regarding Multi-Threading
Top Forums Programming Regarding Multi-Threading Post 78060 by matrixmadhan on Friday 15th of July 2005 04:16:56 AM
Old 07-15-2005
Regarding Multi-Threading
Hi All,

Here's my question
I have a 385 MB file containing 5,000,000 records.
I need to read from the file and load into a table.

Initially i thought of doing it in a single thread (execution of a single program) but when calculated accounted 16 hours of time on a standard benchmark.
Hence decided to do the same in multi-threaded way.

Here's the pseudo-code
total no of bytes in file: k
no of threads: n

for every 1,000,000 records
create a thread with file position pointer
k->k/1,000,000 with access upto (startpos, endpos to which it can access)
next thread would account for insertion of 1x10^6 to 2x10^6
with file postion pointers from k/1x10^6->k/2x10^6
similary continue for all other threads.

I havent tried this yet, i have following questions
regarding this.
a) do i need to have a separate lock when accesing the single file,
b)or there any chances of the file being corrupted.
c)any other memory or lock issues possible.
d)I would like to perform insertion operation quickly
any inputs and ideas greatly appreciated.
e)i definitely know that this is not such a great way any other way for achiveing the purpose would be of great help.

It would also be great if u suggest some websites for executing multiple threads concurrently.
 

10 More Discussions You Might Find Interesting

1. Programming

Multi threading using posix thread library

hi all, can anyone tell me some good site for the mutithreading tutorials, its application, and some code examples. -sushil (2 Replies)
Discussion started by: shushilmore
2 Replies

2. Programming

Multi-threading questions

I've been doing some reading lately about threading (Posix threads) and I'm really curious about a couple things that I've read. I'm not sure if many people here have threading experience, but I thought it would be nice to be able to discuss some questions about it. (For the record, I did... (1 Reply)
Discussion started by: DreamWarrior
1 Replies

3. Programming

Multi threading using fork

Hi, I have written a code which will run a set of process using fork. I want to know from You how can i start another job when one of my job in my loop is completed My code is #include<stdio.h> #include<ctype.h> main() { int pid,cid; ChildProcess(); ... (1 Reply)
Discussion started by: sureshraju_ma
1 Replies

4. Programming

Multi threading?

I am not sure if multi threading is the correct term, but here is what I am trying to do. I have a while loop that displays the number 1, pauses, displays the number 2, pauses , displays the number 3 ad infinitum. It just keeps counting. While the screen displays the sequence of numbers counting... (4 Replies)
Discussion started by: enuenu
4 Replies

5. Programming

Multi-threading-- calling same function through different threads

Sir, Can I call same function in the start routines of different Threads. I have created two different threads....and wanna call same function from both threads....is it possible??? Also can I fork inside a thread??? (1 Reply)
Discussion started by: arunchaudhary19
1 Replies

6. Programming

Multi-threading

Hi, If we create 10 threads to invoke runQuery method at same time, Will queryProcessor will be overriden sometime or 10 different copies will be created? We are not using any sunchronzation mechnism in runQuery(). so there is not gurantee on QueryProcessor class variables right OR each 10... (1 Reply)
Discussion started by: jramesh1
1 Replies

7. Programming

Multi-threading

In this piece i implemented the gossip method. The first thread is invoked from inside the (msg is first sent from node -1 to 0 from main()) and the other threads are invoked from inside of the thread function itself. I used two mutexes and a condition variable to control the synchronization. ... (4 Replies)
Discussion started by: saman_glorious
4 Replies

8. UNIX for Dummies Questions & Answers

Confusion over Multi Threading

Hi, I am trying to get my head round Multi Threading and I have a few queries to try and clear up my confusion Q1. Is multi threading a hardware / chip level concept, an OS level or an application level concept ? I am trying to work out where SMT architecture fits in. Q2. What's the multi... (3 Replies)
Discussion started by: jimthompson
3 Replies

9. UNIX for Beginners Questions & Answers

Does UNIX support multi-Threading ?

Not just background process running ... but im looking if unix has any multi-threading concept like in Java, C# ... if not present, can you pls share the nearest feature in unix that is close to multi-threaded concept (3 Replies)
Discussion started by: i4ismail
3 Replies

10. UNIX for Beginners Questions & Answers

Multi threading in UNIX

Hi, Can we apply multi threading in Unix. I am using bash shell. We have a generic script to load the data to table based on file input. For each file there is an individual table to load. For each file found in directory I want to load the data in parallel to target table using ... (3 Replies)
Discussion started by: vedanta
3 Replies

LEARN ABOUT LINUX

envext

ENVEXT(1)						  The Canonical Csound Reference						 ENVEXT(1)

NAME

       envext - Extracts the envelope of a file to a text file. .

SYNTAX

	   envext [-flags] soundfile

	   csound -U envext [-flags] soundfile

INITIALIZATION

       soundfile - Name of the input soundfile.

       The following flags are available for envext (The default values are stated in parenthesis):
	   -o fnam Name of output filename (newenv)
	   -w size (in seconds) of analysis window (0.25)

       The envext utility generates a text file containing time and amplitude pairs by finding the absolute peak within each window.

EXAMPLE

       Using the command (while in the manual directory):

	   csound -U envext examples/mary.wav

       will produce the a text file containing the following:

	     0.000   0.000
	     0.000   0.000
	     0.250   0.000
	     0.500   0.000
	     0.750   0.000
	     1.249   0.170
	     1.499   0.269
	     1.530   0.307
	     1.872   0.263
	     2.056   0.304
	     2.294   0.241
	     2.570   0.216
	     2.761   0.178
	     3.077   0.011
	     3.251   0.001
	     3.500   0.000

       Which shows the time for the peak amplitude within each measured window.

CREDITS

       Author: John ffitch

       1995

AUTHORS

       Barry Vercoe
       MIT Media Lab

	   Author.

       Dan Ellis
       MIT Media Lab,
		 Cambridge
		 Massachussetts

	   Author.

COPYRIGHT

5.07								    06/23/2009								 ENVEXT(1)
All times are GMT -4. The time now is 01:41 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy