.\" -*- mode: troff; coding: utf-8 -*-
.\" Automatically generated by Pod::Man 5.01 (Pod::Simple 3.43)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" \*(C` and \*(C' are quotes in nroff, nothing in troff, for use with C<>.
.ie n \{\
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is >0, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{\
.    if \nF \{\
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{\
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\" ========================================================================
.\"
.IX Title "LEI-STORE-FORMAT 5"
.TH LEI-STORE-FORMAT 5 1993-10-02 public-inbox.git "public-inbox user manual"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH NAME
lei\-store\-format \- lei/store format description
.SH DESCRIPTION
.IX Header "DESCRIPTION"
\&\f(CW\*(C`lei/store\*(C'\fR is a hybrid store based on \fBpublic\-inbox\-extindex\-format\fR\|(5)
("extindex") combined with \fBpublic\-inbox\-v2\-format\fR\|(5) ("v2") for blob
storage.  While v2 is ideal for archiving a single public mailing list;
it was never intended for personal mail nor storing multiple
blobs of the "same" message.
.PP
As with extindex, it can index disparate \f(CW\*(C`List\-Id\*(C'\fR headers
belonging to the "same" message with different git blob OIDs.
Unlike v2 and extindex, \f(CW\*(C`Message\-ID\*(C'\fR headers are NOT required;
allowing unsent draft messages to be stored and indexed.
.SH "DIRECTORY LAYOUT"
.IX Header "DIRECTORY LAYOUT"
Blob storage exists in the form of v2\-style epochs.  These epochs
are under the \f(CW\*(C`local/\*(C'\fR directory (instead of \f(CW\*(C`git/\*(C'\fR) to
prevent them from being accidentally treated as a v2 inbox.
.SS "INDEX OVERVIEW AND DEFINITIONS"
.IX Subsection "INDEX OVERVIEW AND DEFINITIONS"
.Vb 3
\&  $EPOCH \- Integer starting with 0 based on time
\&  $SCHEMA_VERSION \- DB schema version (for Xapian)
\&  $SHARD \- Integer starting with 0 based on parallelism
\&
\&  ~/.local/share/lei/store
\&  \- local/$EPOCH.git                # normal bare git repositories
\&  \- mail_sync.sqlite3               # sync state IMAP, Maildir, NNTP
.Ve
.PP
Additionally, the following share the same roles they do in extindex:
.PP
.Vb 5
\&  \- ei.lock                         # lock file to protect global state
\&  \- ALL.git                         # empty, alternates for local/*.git
\&  \- ei$SCHEMA_VERSION/$SHARD        # per\-shard Xapian DB
\&  \- ei$SCHEMA_VERSION/over.sqlite3  # overview DB for WWW, IMAP
\&  \- ei$SCHEMA_VERSION/misc          # misc Xapian DB
.Ve
.SS "XREF3 DEDUPLICATION"
.IX Subsection "XREF3 DEDUPLICATION"
Index deduplication follows extindex, see
"XREF3 DEDUPLICATION" in \fBpublic\-inbox\-extindex\-format\fR\|(5) for
more information.
.SS "BLOB DEDUPLICATION"
.IX Subsection "BLOB DEDUPLICATION"
The contents of \f(CW\*(C`local/*.git\*(C'\fR repos is deduplicated by git blob
object IDs (currently SHA\-1).  This allows multiple copies of
cross-posted and personally Cc-ed messages to be stored with
different \f(CW\*(C`Received:\*(C'\fR, \f(CW\*(C`X\-Spam\-Status:\*(C'\fR and similar headers to
allow troubleshooting.
.SS "VOLATILE METADATA"
.IX Subsection "VOLATILE METADATA"
Keywords and label information (as described in RFC 8621 for JMAP)
is stored in existing Xapian shards (\f(CW\*(C`ei$SCHEMA_VERSION/$SHARD\*(C'\fR).
It is possible to search for messages matching labels and
keywords using \f(CW\*(C`L:\*(C'\fR and \f(CW\*(C`kw:\*(C'\fR, respectively.  As with all data
stored in Xapian indices, volatile metadata is associated with
the Xapian document, thus it is shared across different blobs of
the "same" message.
.SS mail_sync.sqlite3
.IX Subsection "mail_sync.sqlite3"
This SQLite database maintained for bidirectional mapping of
git blobs to IMAP UIDs, Maildir file names, and NNTP article numbers.
.PP
It is also used for retrieving messages from Maildirs indexed by
\&\fBlei\-index\fR\|(1).
.SH IPC
.IX Header "IPC"
\&\fBlei\-daemon\fR\|(8) communicates with the \f(CW\*(C`lei/store\*(C'\fR process using
\&\fBunix\fR\|(7) \f(CW\*(C`SOCK_SEQPACKET\*(C'\fR sockets.
.SH CAVEATS
.IX Header "CAVEATS"
Reindexing and synchronization is not yet supported.
.SH THANKS
.IX Header "THANKS"
Thanks to the Linux Foundation for sponsoring the development
and testing.
.SH COPYRIGHT
.IX Header "COPYRIGHT"
Copyright 2021 all contributors <mailto:meta@public\-inbox.org>
.PP
License: AGPL\-3.0+ <http://www.gnu.org/licenses/agpl\-3.0.txt>
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fBpublic\-inbox\-v2\-format\fR\|(5), \fBpublic\-inbox\-extindex\fR\|(5)