Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: How to read a fast written log file at Real time speed?
Top Forums UNIX for Advanced & Expert Users How to read a fast written log file at Real time speed? Post 302937623 by cool.aquarian on Friday 6th of March 2015 03:15:47 PM
Old 03-06-2015
Hi there..

I managed to improve the performance by 10-fold for real time reading.

I analysed and found that most time was being taken by
Code:
while IFS= read -r line

I replaced the while loop with awk to read a single logical unit(each about 6000 lines) in one go.

Code:
tail -F --lines=10000000 --retry --max-unchanged-stats=10 "$FILE_NAME" | awk -f awk-script.txt

Now the speed of reading is able to more than keep up with speed of write.
Even when the file gets rolled over, it is able to catch-up with the new file and gives message like:
tail: `<file-name>' has been replaced; following end of new file
Last edited by cool.aquarian; 03-06-2015 at 06:40 PM..
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

log users real time

hi.... how i can configurator a log file on real time....on unix solaris.... thanks a lot.... Best Regards... (3 Replies)
Discussion started by: chanfle
3 Replies

2. Shell Programming and Scripting

Real time log file redirect

Hi all, i would like to write the shell script program, it can monitor the access_log "real time" when the access_log writing the line contain "abcdef" the program will be "COPY" this line into a file named "abcdef.txt", do the same thing if the contain "123456" "COPY" it into a file named... (3 Replies)
Discussion started by: eric_wong_ch
3 Replies

3. Shell Programming and Scripting

Perl or Shell script to read a transaction log in real time

Hello, I have a Apache webserver running on RedHat. Its primary function is a proxy server for users accessing the internet. I have a transaction log that logs every transactions of every users. For users trying to access certain sites/content the transactions goes into a 302 redirect loop and... (2 Replies)
Discussion started by: bruno406
2 Replies

4. Programming

Read/Write a fairly large amount of data to a file as fast as possible

Hi, I'm trying to figure out the best solution to the following problem, and I'm not yet that much experienced like you. :-) Basically I have to read a fairly large file, composed of "messages" , in order to display all of them through an user interface (made with QT). The messages that... (3 Replies)
Discussion started by: emitrax
3 Replies

5. Filesystems, Disks and Memory

data from blktrace: read speed V.S. write speed

I analysed disk performance with blktrace and get some data: read: 8,3 4 2141 2.882115217 3342 Q R 195732187 + 32 8,3 4 2142 2.882116411 3342 G R 195732187 + 32 8,3 4 2144 2.882117647 3342 I R 195732187 + 32 8,3 4 2145 ... (1 Reply)
Discussion started by: W.C.C
1 Replies

6. Shell Programming and Scripting

Read/Search file being written to giving error due to timing issues

The following is a piece of code to rename LOG_FILE_NEW to LOG_FILE once you get a result (either RUNNING or SHUTDOWN) RESULT="" sleep 30 while ; do sleep 10 RESULT=`sed -n '/RUNNING/'p ${LOG_FILE_NEW}` if ; then RESULT=`sed -n '/SHUTTING_DOWN/'p ${LOG_FILE_NEW}` fi done mv... (3 Replies)
Discussion started by: sonorous
3 Replies

7. HP-UX

HP-UX real time audit log writing

Hey all, I have a problem I was hoping to get some help on. So I have my two auditfiles, audfile1 and audfile2 that can be written to, I want to have the text version of them write to an NFS mount that I have set up. So i already know that i can do .secure/etc/audsp audfile1 > //nfsmount/folder/... (5 Replies)
Discussion started by: CleverRiver6
5 Replies

8. Shell Programming and Scripting

[solved] How to see log in real time?

Hi people I have a bash script with a line like this: python example.py >> log & But i can't see anything in the log file while python program is running only if the program ends seems to write the log file. "$ cat log" for example don't show anything until the program ends. Is there... (4 Replies)
Discussion started by: Tieso
4 Replies

9. Shell Programming and Scripting

Archiving or removing few data from log file in real time

Hi, I have a log file that gets updated every second. Currently the size has grown to 20+ GB. I need to have a command/script, that will try to get the actual size of the file and will remove 50% of the data that are in the log file. I don't mind removing the data as the size has grown to huge... (8 Replies)
Discussion started by: Souvik Patra
8 Replies

10. Shell Programming and Scripting

Log all the commands input by user at real time in /var/log/messages

Below is my script to log all the command input by any user to /var/log/messages. But I cant achieve the desired output that i want. PLease see below. function log2syslog { declare COMMAND COMMAND=$(fc -ln -0) logger -p local1.notice -t bash -i -- "$USER:$COMMAND" } trap... (12 Replies)
Discussion started by: invinzin21
12 Replies

LEARN ABOUT DEBIAN

fstrace_clear

FSTRACE_CLEAR(8)					       AFS Command Reference						  FSTRACE_CLEAR(8)

NAME

       fstrace_clear - Clears the trace log

SYNOPSIS

       fstrace clear [-set <set name>+]
	   [-log <log name>+]
	   [-help]

       fstrace c [-s <set name>+]
	   [-l <log name>+] [-h]

DESCRIPTION

       The fstrace clear command erases the contents of the trace log from kernel memory, but leaves kernel memory allocated for the log.

OPTIONS

       -set <set name>+
	   Names the event set for which to clear the associated trace log.  The only acceptable value is "cm" (for which the associated trace log
	   is "cmfx"). Provide either this argument or the -log argument, or omit both to clear the "cmfx" log by default.

       -log <log name>+
	   Names the trace log to clear. The only acceptable value is "cmfx". Provide either this argument or the -set argument, or omit both to
	   clear the "cmfx" log by default.

       -help
	   Prints the online help for this command. All other valid options are ignored.

EXAMPLES

       The following command clears the "cmfx" trace log on the local machine:

	  # fstrace clear

PRIVILEGE REQUIRED

       The issuer must be logged in as the local superuser "root".

SEE ALSO

       fstrace(8), fstrace_lslog(8), fstrace_lsset(8)

COPYRIGHT

       IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

       This documentation is covered by the IBM Public License Version 1.0.  It was converted from HTML to POD by software written by Chas
       Williams and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.

OpenAFS 							    2012-03-26							  FSTRACE_CLEAR(8)
All times are GMT -4. The time now is 02:31 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy