Bug 33558 - Poor performance of libnss-db on large db files
Summary: Poor performance of libnss-db on large db files
Status: UNCONFIRMED
Alias: None
Product: glibc
Classification: Unclassified
Component: nss (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
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Reported: 2025-10-21 05:41 UTC by Ponnuvel Palaniyappan
Modified: 2025-10-21 09:44 UTC (History)
1 user (show)

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Proposed patch (585 bytes, patch)
2025-10-21 06:40 UTC, Ponnuvel Palaniyappan 		Details | Diff
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Description Ponnuvel Palaniyappan 2025-10-21 05:41:25 UTC 
libdnss-db opens and closes the DB file each time. This is normally not an issue as the DB files are small. This results in considerably poor performance when the DB files large (e.g. in an environment with 20k lines of DB file, the performance was 40times compared to keeping it open for processing all lines).

Rather than re-opening for scanning each line, the file can be kept open for each call into libnss as proposed in [1].


Reported elsewhere:

[0] https://bugs.launchpad.net/ubuntu/+source/libnss-db/+bug/2121543
[1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1101371
Comment 1 Ponnuvel Palaniyappan 2025-10-21 06:40:17 UTC 
Created attachment 16429 [details]
Proposed patch

Attaching the proposed patch here. Also sent to glibc-alpha.