Bug 210876
| Summary: | 'grep' takes minutes to complete the operation if using invert-match and "or" | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 4 | Reporter: | theresa.chin |
| Component: | grep | Assignee: | Tim Waugh <twaugh> |
| Status: | CLOSED ERRATA | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | 4.2 | ||
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | ia64 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2006-10-17 13:39:42 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
Please try the package from the latest update (Update 4), which contains several
changes to address performance problems.
Alternatively if your search pattern contains no '.' or non-ASCII characters,
you can speed the operation up significantly by getting grep to process the
input as ASCII instead of the default UTF-8. Just set 'LC_CTYPE=C' in the
environment ('export LC_CTYPE=C' in bash).
Thank you for the solution. We've tried the latest update version of grep 'grep-2.5.1-32.2.ia64.rpm' and the slow operation problem has been solved. Best regards, Theresa Chin |
From Bugzilla Helper: User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.0.3705; .NET CLR 1.1.4322; .NET CLR 2.0.50727) Description of problem: To be clear, this appears to be a RHEL4 Intel issue. This has been reproduced on IA64 servers and EMT64 workstation. It does *not* occur on an AMD Opteron WS. If a grep is constructed such that an extended "or" and invert-match which causes a large number of files to be omitted are used, the time it takes to complete the operation is in minutes even though it should take sub-seconds. Below are some examples showing the individual operations taking a few seconds, but when adding the "or", it takes minutes. This was done against a 5mb text file. On the AMD opteron using the same command/file, it takes .3 seconds! [root@can16 ~]# time egrep -iv '100' /boot/System.map|wc 61 183 2601 real 0m0.232s user 0m0.228s sys 0m0.003s [root@can16 ~]# time egrep -iv '200' /boot/System.map|wc 21183 63549 837563 real 0m0.164s user 0m0.267s sys 0m0.002s [root@can16 ~]# time egrep -iv '100|200' /boot/System.map|wc 60 180 2553 real 0m40.504s user 0m40.398s sys 0m0.018s [root@can16 ~]# We need a fix for this from Red Hat. Version-Release number of selected component (if applicable): grep-2.5.1-31 How reproducible: Always Steps to Reproduce: 1. Create a large text file (e.g. 5 MB text file) to search pattern. 2. Do the 'egrep' operation on the file with "or" and invert-match to cause a large number of files to be omitted. 3. Time the operation for completion. See the examples in the bug Description. Actual Results: The grep operation with -E (egrep) and "or" and "invert-match" took minutes to complete. Expected Results: The operation should have taken sub-seconds. Additional info: