1LEI-STORE-FORMAT(5) public-inbox user manual LEI-STORE-FORMAT(5)
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6 lei-store-format - lei/store format description
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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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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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68 lei-daemon(8) communicates with the "lei/store" process using unix(7)
69 "SOCK_SEQPACKET" sockets.
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72 Reindexing and synchronization is not yet supported.
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75 Thanks to the Linux Foundation for sponsoring the development and
76 testing.
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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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84 public-inbox-v2-format(5), public-inbox-extindex(5)
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88public-inbox.git 1993-10-02 LEI-STORE-FORMAT(5)