=head1 NAME

public-inbox-xcpdb - upgrade Xapian DB formats

=head1 SYNOPSIS

public-inbox-xcpdb [OPTIONS] INBOX_DIR

public-inbox-xcpdb [OPTIONS] --all

=head1 DESCRIPTION

public-inbox-xcpdb is similar to L<copydatabase(1)> for
upgrading to the latest database format supported by Xapian
(e.g. "glass" or "honey"), but is designed to tolerate and
accept parallel Xapian database modifications from
L<public-inbox-watch(1)>, L<public-inbox-mda(1)>,
L<public-inbox-learn(1)>, and L<public-inbox-index(1)>.

This command is rarely used, as Xapian DB formats rarely
change.

=head1 OPTIONS

=over

=item --all

Copy all inboxes configured in ~/.public-inbox/config.
This is an alternative to specifying individual inboxes directories
on the command-line.

=item -c

=item --compact

In addition to performing the copy operation, run L<xapian-compact(1)>
on each Xapian shard after copying but before finalizing it.
Compared to the cost of copying a Xapian database, compacting a
Xapian database takes only around 5% of the time required to copy.

Compared to L<public-inbox-compact(1)>, use of this option is
preferable for gigantic inboxes where the coarse-grained lock
currently required for L<public-inbox-compact(1)> can cause
the compaction to take hours at-a-time.

=item -R N

=item --reshard=N

Reshard the Xapian database on a L<v2|public-inbox-v2-format(5)>
inbox to C<N> shards .  Since L<xapian-compact(1)> is not suitable
for merging, users can rely on this switch to reshard the
existing Xapian database(s) to any positive value of C<N>.

This is useful in case the Xapian DB was created with too few or
too many shards given the capabilities of the current hardware.

=item --blocksize

=item --no-full

=item --fuller

These options are passed directly to L<xapian-compact(1)> when
used with C<--compact>.

=item --no-fsync

Disable L<fsync(2)> and L<fdatasync(2)>.
See L<public-inbox-index(1)/--no-fsync> for caveats.

Available in public-inbox 1.6.0+.

=item --sequential-shard

Copy each shard sequentially, ignoring C<--jobs>.  This also
affects indexing done at the end of a run.

=item --batch-size=BYTES

=item --max-size=BYTES

See L<public-inbox-index(1)> for a description of these options.

These indexing options indexing at the end of a run.
C<public-inbox-xcpdb> may run in parallel with with
L<public-inbox-index(1)>, and C<public-inbox-xcpdb> needs to
reindex changes made to the old Xapian DBs by
L<public-inbox-index(1)> while it was running.

=back

=head1 ENVIRONMENT

=over 8

=item PI_CONFIG

The default config file, normally "~/.public-inbox/config".
See L<public-inbox-config(5)>

=item XAPIAN_FLUSH_THRESHOLD

The number of documents to update before committing changes to
disk.  This environment is handled directly by Xapian, refer to
Xapian API documentation for more details.

Default: 10000

=back

=head1 UPGRADING

This tool is intended for admins upgrading Xapian search databases
used by public-inbox, NOT users upgrading public-inbox itself.

In particular, it DOES NOT upgrade the schema used by the
PSGI search interface (see L<public-inbox-index(1)>).

=head1 LIMITATIONS

Do not use L<public-inbox-purge(1)> or L<public-inbox-edit(1)>
while this is running; old (purged or edited data) may show up.

Normal invocations L<public-inbox-index(1)> can safely run
while this is running, too.  However, reindexing via the
L<public-inbox-index(1)/--reindex> switch will be a waste of
computing resources.

=head1 CONTACT

Feedback welcome via plain-text mail to L<mailto:meta@public-inbox.org>

The mail archives are hosted at L<https://public-inbox.org/meta/> and
L<http://4uok3hntl7oi7b4uf4rtfwefqeexfzil2w6kgk2jn5z2f764irre7byd.onion/meta/>

=head1 COPYRIGHT

Copyright 2019-2021 all contributors L<mailto:meta@public-inbox.org>

License: AGPL-3.0+ L<https://www.gnu.org/licenses/agpl-3.0.txt>

=head1 SEE ALSO

L<copydatabase(1)>, L<xapian-compact(1)>, L<public-inbox-index(1)>