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NAME

       nnmaster - nn database manager

SYNOPSIS

       nnmaster -I [lmit]
       nnmaster -w
       nnmaster -v
       nnmaster -l [ "lock message" ]
       nnmaster [ options ] [ groups ]
       nnmaster -F [ options ] [ groups ]

DESCRIPTION

       nnmaster is the daemon which is responsible for building and maintaining the database used
       by the nn(1) news reader.

       Normally, nnmaster is started when the system  enters  multi-user  mode,  and  runs  until
       system  shutdown.   To facilitate this, you should place the following call in /etc/rc (or
       similar) to invoke the nnmaster daemon:
            $master/nnmaster -l -r -C
       where $master is the MASTER_DIRECTORY defined during configuration of nn.

       When nnmaster is started as specified above, it will first unlock the database in case  it
       was locked (-l), perform a thorough consistency check on the database (-C).

       Then, every 10 minutes (-r), it will look at the time-stamp of the news active file to see
       whether new articles have arrived on the system (or whether articles have  been  expired).
       (See -U)

       If  the  active  file has been modified, nnmaster will collect the header information from
       the new articles and enter them into the database (or remove the headers  of  the  expired
       articles from the database).

       If  it  detects  that  some  articles  have been expired, it will automatically remove the
       header information of the expired articles from the database.

ARTICLE COLLECTION OPTIONS

       Normally, nnmaster will collect all available news groups defined in the news active file.
       The set of collected groups can be controlled via the argument line.  Groups can be either
       included or excluded:
       A group name, e.g. comp, will cause the group and  all  its  subgroups  to  be  collected.
       Individual groups, e.g. news.software.nn, can also be specified
       A  group  name  preceded by an exclamation mark, e.g. !talk.politics, will cause the group
       and all its subgroups to be ignored.
       An empty argument, i.e. "", will cause all groups that are not ignored  to  be  collected.
       For example, to collect everything but rec and misc, use the following command:
            nnmaster -r !rec !misc ""
       If  the empty argument had been omitted, nothing would be collected, since the presence of
       any groups arguments causes nnmaster  to  ignore  all  groups  which  are  not  explicitly
       mentioned.
       Example  1:  The  following  commands can be executed by cron to collect different sets of
       groups at different intervals or under different conditions:
            nnmaster -B -O14 rec misc sci -LBO -u
            nnmaster !rec !misc !sci "" -u
       Example 2: The group arguments are used in the given sequence, e.g. to leave out comp.sys,
       but still collect comp.sys.ibm.pc, use the command:
            nnmaster -r comp.sys.ibm.pc !comp.sys ""
       The  use  of  the  -u option in the first example is essential, since each of the commands
       will update the active file time stamp which will prevent the other command from detecting
       new articles that have arrived.
       Using  this  method  to  keep  specific groups out of the database must be used with great
       caution; just a single invocation of nnmaster without any arguments will collect  all  the
       otherwise ignored groups!

COLLECTION OF ARTICLES

       The following options control how nnmaster performs the collection of new articles.

       -r [ min ]
              Daemon  mode.   The  nnmaster  will put itself in the background (unless -f is also
              specified), and will checks for arrival of new articles and expired articles  every
              min  minutes (and update the database accordingly).  If min is omitted, the default
              is to check every 10 minutes.
              Without the -r option, the nnmaster will just perform a single  collection  of  new
              articles  (if any) and then exit.  This can be used to have the nnmaster started by
              cron(8) at regular intervals instead of having it as a daemon which sleeps  between
              checking  for  new articles.  Since the nnmaster is a bit expensive to start up (it
              has to read a few files), it is up to you to decide which  mode  is  best  on  your
              system.   (I  have  also  heard  that  it  works  to  call nnmaster without -r from
              inews(1).  I cannot recommend  this  unless  you  receive  batched  news;  invoking
              nnmaster for every received article sounds too expensive to me.)

       -h [ sec ]
              Hold  collection  of  new  articles  until  next  scan if new articles have arrived
              withing the last sec [60]  seconds.   This  is  useful  to  prevent  nnmaster  from
              competing  for disk i/o with an rnews process which is unbatching incoming news, or
              a running expire process.  It will have the side effect of limiting the  number  of
              C:  entries in the log, since collection of incoming batches will typically be done
              in larger thunks.

       -f     Run nnmaster in foreground in daemon mode (see -r).  Useful if nnmaster is  invoked
              from  inittab.  (Notice that if you use a respawn entry in inittab, you will not be
              able to stop nnmaster using the  -k  option,  since  init  will  immediately  start
              another master.)

       -C     Perform  a  consistency  check  on  the database on start-up, and rebuild corrupted
              database files.  This operation can be quite time-consuming since it reads  through
              all the database files.

       -b     Normally,  articles without a proper news header (no Newsgroups: line) are ignored.
              Specifying the -b option causes these `bad' articles to be included in the database
              (normally with no sender or subject).

       -B     Remove  `bad'  articles.   Sometimes, articles without a header ends up in the news
              spool directory.  These articles have no article id, and therefore, they will never
              be  expired  by  expire(8).  This option will allow the nnmaster to silently remove
              these articles (a `B' entry will occur in the log file).

       -O days
              Ignore articles which are older than the given number of days.  This may help  keep
              old 'stray' articles out of the database.  If the -B options is also specified, the
              old articles will be removed from the  news  spool  directories.   Old  ignored  or
              removed  articles  will be reported with an `O' entry in the log file.  This option
              can be disable for individual groups by the O flag in the GROUPS file (see below).

       -R N   Specifies how the auto-recollect operation is performed on the groups  having  this
              option  set in the GROUPS file (see below).  Four methods are available (default is
              method 1):
              1:  Run expire on the group when new articles arrive.
              2:  Run expire on the group on every scan.
              3:  Recollect all articles when new articles arrive.
              4:  Recollect all articles on every scan.

       -M mode
              Normally, nnmaster will send a message via mail to the news  administrator  (OWNER)
              when  an  error  or potential problems (primarily nntp related) occur.  This can be
              restricted to only fatal errors (nnmaster terminated) if mode is  1,  and  disabled
              completely if mode is 0.

       -Q     Normally, nnmaster will print a message on the system console or in the syslog if a
              fatal error happens.  This option will prevent this, so only a type  'E'  entry  is
              written to the Log file.

DATABASE EXPIRATION

       Since  articles  does not stay forever in the news system, the database must be cleaned up
       regularly to remove the information  stored  for  expired  articles.   Expiration  of  the
       database  is  normally  scheduled  using  the  nnadmin(1M)  command  executed by cron at a
       suitable time when expire on the news articles has completed.  The following command  will
       send a message to the nnmaster and cause it to initiate expire on all news groups:
            nnadmin =EYW

       Selective expiration of individual groups can be done from nnadmin (interactive mode).  It
       can also be done by invoking nnmaster with the -F  option.   For  example,  the  following
       command will run expire on all groups except the `rec' groups:
            nnmaster -F -k !rec ""
       The  -k  option  is  required  to terminate the currently running master since two daemons
       cannot be running at the same time.  Thus to run expire (on all groups) in this  way  from
       cron, the following commands must be used:      nnmaster -Fk "" ; nnmaster -r ...

       It  is  also  possible  to  have  nnmaster detect expiration automatically (see -e).  This
       requires that the min field in the active file is updated by the news expire (this is  not
       the default case when Cnews is used).  However, this is not always a safe indication since
       the first article may not have been expired, while a  lot  of  other  articles  have  been
       deleted.

       There  are  several  strategies available in the nnmaster to do this clean-up, each having
       their strengths and weaknesses.

       Method 1 (default):  Rebuilds the database  from  the  existing  database  information  by
       comparing  the  current database contents with the contents of the news group directories,
       eliminating entries whose file no longer exists.  This method is guaranteed  to  eliminate
       all  expired  articles from the database, and it is reasonably fast because it only has to
       read the directories, not each article file.
         If news is accessed remotely via nntp, the list of existing articles cannot  efficiently
       be  fetched  by  reading  a  local directory.  Instead an XHDR request is sent to the nntp
       server to get a list of articles.

       Method 2:  Eliminates only the expired articles before the first  article  in  the  group.
       This  is  very fast since only the active file and the database itself is accessed, but it
       will obviously leave some expired articles in the database.  This method requires that the
       min field in the active file is updated by expire.

       Method  3:  Discard the current database information and recollects all articles.  This is
       obviously very time consuming, and it is therefore not recommended,  especially  not  with
       nntp.

       The options related to database expiration are:

       -E N   Select expire method N.  (If N is omitted, the default method is used).

       -e [N] Automatically  run  expire  in  the  database on groups where the min number in the
              active file has increased by N (1  if  omitted)  articles.   This  is  disabled  by
              default (since the min field is often unreliable).

       -F     Run  expire  once  and exit.  If a list of groups is specified on the command line,
              the matched groups (see the rules above) will be  marked  for  expiration.   If  no
              groups are specified, only the groups already scheduled for expire will be expired.
              Consequently, to expire all groups, a blank argument "" (matching all groups)  must
              be specified.

DATABASE LOCKING

       The  database  can  be  locked  centrally,  which will normally disallow all access to the
       database, and even block nnmaster from being (accidentally) started.  When a lock  is  set
       on  the  database,  all currently running clients will terminate the next time they try to
       access the database.  Setting a lock on the database  can  thus  also  be  used  to  force
       running clients to terminate.

       The following options set and clear locks on the database:

       -l message
              Locks  the  database  with  the given message.  The message will be displayed every
              time a program tries to access the database.

       -l     Unlock the database if it was locked.

       -i     Ignore a possible lock and continue.  This can be used to have nnmaster operate  on
              a database which is blocked from normal user access.

       Since  only  one  nnmaster can operate on the database at any one time, a running nnmaster
       daemon must be stopped before a lock can be set on the database.  If neither -f nor -r  is
       specified  with  the  -l  option (in both forms), nnmaster will terminate after setting or
       clearing the lock.

DATABASE INITIALIZATION

       The following options are used to initialize and update the central database files:

       -I [limit]
              Initialize database.  This option will erase an existing database,  and  create  an
              empty  database  containing  entries for the currently known groups.  nnmaster will
              offer you to use an existing GROUPS file when initializing the database.
              The optional limit can be used to put a limit on the number of articles  that  will
              be  collected  in  each group during the first collection of articles following the
              database initialization.  This is useful on systems where the 'min'  field  in  the
              active  file is unreliable or not maintained (Cnews doesn't) to limit the work done
              to do the initial collection of news after the initialization of the database.   If
              news  is  accessed  remotely  from an NNTP server, this is even more important!  If
              limit is omitted, or is zero, nnmaster will trust the min  field  and  collect  all
              articles in the range min..last.

       -G     Reread  the  GROUPS  file.   This  option is used to instruct nnmaster to parse the
              GROUPS file after it has been edited.  See the section on the GROUPS file below.

MISCELLANEOUS OPTIONS

       The following options controls various details of the nnmaster's behaviour:

       -D [ N ]
              Run nnmaster in "debug mode".  If N is omitted, or equals 1 or 3, this will produce
              a  compact  but  still  very  informative trace of the collection or expire process
              directly on the terminal.  This is most useful when doing the first  collection  of
              articles  after  initializing the database with -I.  If N is 2 or 3, a trace of the
              NNTP traffic is written to a file nnmaster.log in the TMP  directory.  This  option
              disables -r.

       -H     Identifies  the  host  which  nnmaster  is  running  on  as the nntp-server for its
              clients, i.e. that it can access the news spool  directory  locally  without  using
              NNTP.   Normally, nnmaster will detect this by itself by comparing the host name to
              the contents of the nntp_server file, so this option should really be superfluous.

       -y retries
              In some networked environment, opening an article (shared from another machine  via
              NFS)  may  fail  for no obvious reason.  Using this option, it is possible to cause
              nnmaster to perform retries attempts to open an article before marking the  article
              as non-existing in the database.

       -L types
              Exclude  the  specified  entry  types  from the log file.  This is normally used to
              exclude the 'C'ollecting and e'X'pire entries (-LCXO).

       -t     Trace the collection process.  This will place a lot of information  into  the  log
              file (T: entries).

       -u     Normally, nnmaster will just compare the time-stamp on the active file with a time-
              stamp saved in the database to see if new articles have  arrived.   The  -u  option
              forces the nnmaster to read the active file on start-up to see if new articles have
              arrived.

       -U     Some SVR4 systems (and maybe SunOS) have a useful "feature".   Writing  files  with
              mmap()  may  not  update  the  last-changed  timestamp on the file.  Since INN uses
              mmap() for writing the active file, this becomes a problem for  nnmaster.   The  -U
              option causes nnmaster to unconditionally read the active file each time the repeat
              delay (-r) time expires.

       -v     Print the release and version identification for nnmaster, and exit.

       -w     Wakeup the real nnmaster.  Send a signal to the nnmaster daemon to  have  it  check
              for new articles immediately.

       -k     Kill  the  already  running  nnmaster  daemon  before proceeding with the operation
              specified by the other options (or terminate if no other operation is requested).

THE GROUPS FILE

       The primary purpose of the  GROUPS  file  is  to  store  the  names  of  the  news  groups
       represented  in  the  database.   Each  line  in  the  file corresponds to an entry in the
       (binary) MASTER file, and the sequence of the lines in  the  GROUPS  file  must  never  be
       changed unless the database is reinitialized afterwards.

       However,  the  contents  of  the lines in the GROUPS file can be edited to control how the
       nnmaster should handle each individual group.

       The format of each line is:
            news.group.name [ timestamp ] [ flags ]

       The news group name is the name of the group, and must not be changed in any way.  If  the
       group  is  no  longer  in  the news active file, and consequently the group does no longer
       exist, group name can be replaced by a `@'  character  which  will  instruct  nnmaster  to
       ignore this entry without having to rebuild the entire database.

       The  optional  time stamp indicates when the line was added to the GROUPS file and is used
       by nn to detect new groups.  When the GROUPS file is built initially from the active file,
       the time stamps are omitted which simply means that they are "old".

       One  or  more of the following flags can be added to the GROUPS line to control nnmaster's
       handling of the group:

       D      Causes nnmaster to treat all articles in the group as digests, even when they don't
              initially look like digests.  Articles which are found not to be digests after all,
              are still not digested.

       N      Instructs nnmaster to never digest any articles in the group.

       O      Disables the -O option for this group, i.e. all existing articles will be  included
              in the database (and they will not be removed if the -B option is specified).  This
              flag should be set on groups which you never expire, or have  a  very  long  expire
              time!

       R      Causes  nnmaster  to  recollect  all available articles in the group whenever a new
              article is received.  This is said to  be  useful  is  some  high-traffic  clarinet
              groups with many cancelled articles.

       >file  Instructs nnmaster to append all new articles to the specified file.  This makes it
              possible to keep specific groups out of the way of expire.  The archive file can be
              access  directly  from  the  nn client using the goto-group command.  The file name
              must be a full path name to a file in an existing, writeable directory.

       @      Instructs nnmaster to completely ignore this group - this is equivalent to  setting
              the group name to `@' as described above.

       ! or X Causes  nnmaster  to  ignore  the group and not collect the group's articles in the
              database.

       Comments (starting with `#' and continuing to the end of line) and empty lines  are  allow
       in  the GROUPS file, but it is strongly recommended to keep the changes to the GROUPS file
       as small as possible, because of the implicit correspondence with the binary MASTER file.

       It is not recommended to edit the GROUPS file while nnmaster is running because it may add
       new groups to the file.  After editing the GROUPS file, the command
            nnmaster -G
       must be run before restarting the nnmaster to parse and verify the new GROUPS file.

NNTP SUPPORT

       The  nnmaster  can  access  the news articles from a local news spool directory as well as
       from an NNTP server.  When compiled with NNTP enabled, nnmaster will compare the  name  of
       the  NNTP  server  and  the  name  of the local host; if they are identical, nnmaster will
       bypass NNTP and access the articles directly.

       When it has to access the news articles via NNTP, it cannot time-stamp the active file, so
       instead  it  transfers  the entire active file from the NNTP server and compares it with a
       local copy of the last active file fetched  from  the  NNTP  server.   This  is  not  very
       expensive  in  terms  of  cpu-cycles, disk-load, or net-bandwidth, but to stay on friendly
       terms with the NNTP server administrator, you  should  probably  not  use  shorter  update
       intervals than the standard 10 minutes.

       Setting  a  much  higher  update  interval  than  the  standard  10  minutes is not really
       recommended either, since an update normally implies fetching a  burst  of  news  articles
       from the NNTP server, so setting the interval too long may imply that the load on the NNTP
       server will be more un-even.

       In expire method 1, the use of XHDR just to get a list of existing articles in a group  is
       definitely  a waste of resources on the nntp server (but still lower than using method 3).
       Before using the XHDR request, nnmaster will send a non-standard "LISTGROUP"  request;  if
       the  nntp  server supports this request, it should return an OK_HEAD status followed by an
       (unordered) list of article numbers (one per line) terminated by a  `.'  line.   The  nntp
       servers supporting this request will be much less loaded during expire.

       The  -O  option  does  not  work with NNTP.  The -B option will only work with NNTP if the
       nnmaster is running on the NNTP server.

FILES

       The $db,  $master,  and  $news  names  used  below  are  synonyms  for  the  DB_DIRECTORY,
       MASTER_DIRECTORY, and NEWS_LIB_DIRECTORY defined during configuration.

       $db/MASTER          Database master index
       $db/GROUPS          News group names and flags in MASTER file order
       $db/DATA/nnn.[dx]   Database files for group number nnn
       .../.nn[dx]         Database files if located in the group directories
       $master/GATE        Message channel from nnadmin to nnmaster
       $master/MPID        The process id of the nnmaster daemon.
       $Log                The log file (the location is configuration dependent)
       $news/active        Existing articles and groups
       /usr/lib/nntp_serverContains the name of the NNTP server.

       The  MASTER  file contains a record for each news group, occurring in the same sequence as
       the group names in the GROUPS file.  The sequence also defines the group numbers  used  to
       identify the files in the database's DATA directory.

       The  GATE file will be created by nnadmin when needed, and removed by nnmaster when it has
       read it.  Therefore, to send a message to the nnmaster requires that you  are  allowed  to
       write in the $master directory.

       The contents of the Log file are described in the nnadmin manual.

SEE ALSO

       nn(1), nncheck(1), nngrep(1), nntidy(1)
       nnadmin(1M), nnspew(8), nnusage(1M)

AUTHOR

       Kim F. Storm, Texas Instruments A/S, Denmark
       E-mail: storm@texas.dk