lei-store-format(5)

1LEI-STORE-FORMAT(5)        public-inbox user manual        LEI-STORE-FORMAT(5)
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NAME

6       lei-store-format - lei/store format description
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DESCRIPTION

9       "lei/store" is a hybrid store based on public-inbox-extindex-format(5)
10       ("extindex") combined with public-inbox-v2-format(5) ("v2") for blob
11       storage.  While v2 is ideal for archiving a single public mailing list;
12       it was never intended for personal mail nor storing multiple blobs of
13       the "same" message.
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15       As with extindex, it can index disparate "List-Id" headers belonging to
16       the "same" message with different git blob OIDs.  Unlike v2 and
17       extindex, "Message-ID" headers are NOT required; allowing unsent draft
18       messages to be stored and indexed.
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DIRECTORY LAYOUT

21       Blob storage exists in the form of v2-style epochs.  These epochs are
22       under the "local/" directory (instead of "git/") to prevent them from
23       being accidentally treated as a v2 inbox.
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25   INDEX OVERVIEW AND DEFINITIONS
26         $EPOCH - Integer starting with 0 based on time
27         $SCHEMA_VERSION - DB schema version (for Xapian)
28         $SHARD - Integer starting with 0 based on parallelism
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30         ~/.local/share/lei/store
31         - local/$EPOCH.git                # normal bare git repositories
32         - mail_sync.sqlite3               # sync state IMAP, Maildir, NNTP
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34       Additionally, the following share the same roles they do in extindex:
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36         - ei.lock                         # lock file to protect global state
37         - ALL.git                         # empty, alternates for local/*.git
38         - ei$SCHEMA_VERSION/$SHARD        # per-shard Xapian DB
39         - ei$SCHEMA_VERSION/over.sqlite3  # overview DB for WWW, IMAP
40         - ei$SCHEMA_VERSION/misc          # misc Xapian DB
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42   XREF3 DEDUPLICATION
43       Index deduplication follows extindex, see "XREF3 DEDUPLICATION" in
44       public-inbox-extindex-format(5) for more information.
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46   BLOB DEDUPLICATION
47       The contents of "local/*.git" repos is deduplicated by git blob object
48       IDs (currently SHA-1).  This allows multiple copies of cross-posted and
49       personally Cc-ed messages to be stored with different "Received:",
50       "X-Spam-Status:" and similar headers to allow troubleshooting.
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52   VOLATILE METADATA
53       Keywords and label information (as described in RFC 8621 for JMAP) is
54       stored in existing Xapian shards ("ei$SCHEMA_VERSION/$SHARD").  It is
55       possible to search for messages matching labels and keywords using "L:"
56       and "kw:", respectively.  As with all data stored in Xapian indices,
57       volatile metadata is associated with the Xapian document, thus it is
58       shared across different blobs of the "same" message.
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60   mail_sync.sqlite3
61       This SQLite database maintained for bidirectional mapping of git blobs
62       to IMAP UIDs, Maildir file names, and NNTP article numbers.
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64       It is also used for retrieving messages from Maildirs indexed by
65       lei-index(1).
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IPC

68       lei-daemon(8) communicates with the "lei/store" process using unix(7)
69       "SOCK_SEQPACKET" sockets.
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CAVEATS

72       Reindexing and synchronization is not yet supported.
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THANKS

75       Thanks to the Linux Foundation for sponsoring the development and
76       testing.
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COPYRIGHT

79       Copyright 2021 all contributors <mailto:meta@public-inbox.org>
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81       License: AGPL-3.0+ <http://www.gnu.org/licenses/agpl-3.0.txt>
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