EXPIREOVER(8)

NAME
expireover - Expire entries from the news overview database

SYNOPSIS
expireover [-ekNpqs] [-f file] [-w offset] [-z rmfile] [-Z lowmarkfile]

DESCRIPTION
expireover expires old entries from the news overview database. It reads in a list of newsgroups (by default from pathdb/active, but a different file can be specified with the -f option) and then removes from the overview database mentions of any articles that no longer exist in the news spool.

If groupbaseexpiry in inn.conf is true, expireover also removes old articles from the news spool according to the expiration rules in expire.ctl. Otherwise it only removes overview entries for articles that have already been removed by some other process, and -e, -k, -N, -p, -q, -w, and -z are all ignored.

When expiretombstone and groupbaseexpiry are enabled in inn.conf, expireover appends each cancelled token to expireover.tombstone.NEW in pathdb under an exclusive POSIX lock, and atomically renames the file into place on a clean run. In delayrm mode (-z), the rename is performed by expirerm after fastrm succeeds. The next expire run consumes this log to skip per-article storage existence checks. See inn.conf(5) under expiretombstone.

When groupbaseexpiry is set, the default behavior of expireover is to remove the article from the spool once it expires out of all of the newsgroups to which it was crossposted. The article is, however, removed from the overview database of each newsgroup as soon as it expires out of that individual newsgroup. The effect is that an article crossposted to several groups will be removed from the overview database from each group one-by-one as its age passes the expiration threshold for that group as set in expire.ctl, and then when it expires out of the last newsgroup, it will be deleted from the news spool.

Articles that are stored in self-expiring storage backends such as CNFS are normally treated differently and not expired until they expire out of the backend regardless of expire.ctl. See -N, however.

By default, expireover purges all overview information for newsgroups that have been removed from the server; this behavior is suppressed if -f is given.

To speed up the existence check for each article, expireover builds a Bloom filter from the history file at startup. This replaces per-article random I/O into the history file with a single sequential read, which is critical for large spools. The Bloom filter is a positive-only cache: if it reports an article probably exists, the slow history lookup is skipped. If it reports the article is not found, expireover falls back to a direct history lookup for correctness. False positives (the Bloom filter incorrectly reporting an article exists) are benign; the orphaned overview entry will be cleaned up on the next expiration run.

The false positive rate and memory usage of the Bloom filter are controlled by the expirebloomfp setting in inn.conf. Setting it to 0 disables the Bloom filter. The Bloom filter is also disabled when the -s flag is used.

OPTIONS

-e  Remove articles from the news spool and all overview databases as soon as they expire out of any newsgroup to which they are posted, rather than retain them until they expire out of all newsgroups. -e and -k cannot be used at the same time. This flag is ignored if groupbaseexpiry is false.

-f file
    Use file as the newsgroup list instead of pathdb/active. file can be "-" to indicate standard input. Using this flag suppresses the normal purge of all overview information from newsgroups that have been removed from the server.

-k  Retain all overview information for an article, as well as the article itself, until it expires out of all newsgroups to which it was posted. This can cause articles to stick around in a newsgroup for longer than the expire.ctl rules indicate, when they're crossposted. -e and -k cannot be used at the same time. This flag is ignored if groupbaseexpiry is false.

-N  Apply expire.ctl rules to expire articles even from storage methods that have self-expire functionality. This may remove articles from self-expiring storage methods before the articles "naturally" expire. This flag is ignored if groupbaseexpiry is false.

-p  By default, expireover bases decisions on whether to remove an article on the arrival time on the server. This means that articles may be kept a little longer than if the decision were based on the article's posting date. If this option is given, expiration decisions are based on the article posting date instead. This flag is ignored if groupbaseexpiry is false.

-q  expireover normally prints statistics at the end of the expiration process. -q suppresses this report. This flag is ignored if groupbaseexpiry is false.

-s  expireover normally only checks the existence of articles in the news spool if querying the storage method for that article to see if it still exists is considered "inexpensive". To always check the existence of all articles regardless of how resource-intensive this may be, use the -s flag. See storage.conf(5) for more information about this metric.

-w offset
    "Warps" time so that expireover thinks that it's running at some time other than the current time. This is occasionally useful to force groups to be expired or not expired without changing expire.ctl for the expire run. offset should be a signed floating point number specifying the number of days difference from the current time to use as "now". This flag is ignored if groupbaseexpiry is false.

-z rmfile
    Don't remove articles immediately but instead write the path to the article or the token of the article to rmfile, which is suitable input for fastrm(1). This can substantially speed up deletion of expired articles for those storage methods where each article is a single file (such as tradspool and timehash). See the description of the delayrm keyword in news.daily(8) for more details. This flag is ignored if groupbaseexpiry is false.

-Z lowmarkfile
    Write the lowest article numbers for each newsgroup as it's expired to the specified file. This file is then suitable for "ctlinnd lowmark". See ctlinnd(8) for more information.

EXAMPLES
Normally expireover is invoked from news.daily(8), which handles such things as processing the rmfile and lowmarkfile if necessary. Sometimes it's convenient to manually expire a particular newsgroup, however. This can be done with a command like:

    echo example.test | expireover -f - -Z <pathtmp in inn.conf>/lowmark
    ctlinnd lowmark <pathtmp>/lowmark

This can be particularly useful if a lot of articles in a particular group have expired but the overview information is still present, causing some clients to see a lot of "this article may have been cancelled" messages when they first enter the newsgroup.

HISTORY
Written by Rob Robertson <rob@violet.berkeley.edu> and Rich $alz <rsalz@uunet.uu.net> (with help from Dave Lawrence <tale@uunet.uu.net>) for InterNetNews.

SEE ALSO
active(5), ctlinnd(8), expire(8), expire.ctl(5), inn.conf(5), news.daily(8).