X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=Documentation%2Fpublic-inbox-v2-format.pod;h=730f663381069df0b31957a7771f248349ec29c5;hb=95bdac7f09c69036efed537a4d03d5bdd2ae4eb6;hp=65a85c19470835ef6529515421cdefca6575538a;hpb=666f1b8f5c7c76333df4e1296c1668abf04f210f;p=public-inbox.git
diff --git a/Documentation/public-inbox-v2-format.pod b/Documentation/public-inbox-v2-format.pod
index 65a85c19..730f6633 100644
--- a/Documentation/public-inbox-v2-format.pod
+++ b/Documentation/public-inbox-v2-format.pod
@@ -16,21 +16,21 @@ Message-IDs.
The key change in v2 is the inbox is no longer a bare git
repository, but a directory with two or more git repositories.
v2 divides git repositories by time "epochs" and Xapian
-databases for parallelism by "partitions".
+databases for parallelism by "shards".
=head2 INBOX OVERVIEW AND DEFINITIONS
-$EPOCH - Integer starting with 0 based on time
-$SCHEMA_VERSION - PublicInbox::Search::SCHEMA_VERSION used by Xapian
-$PART - Integer (0..NPROCESSORS)
+ $EPOCH - Integer starting with 0 based on time
+ $SCHEMA_VERSION - DB schema version (for Xapian)
+ $SHARD - Integer starting with 0 based on parallelism
-foo/ # assuming "foo" is the name of the list
-- inbox.lock # lock file (flock) to protect global state
-- git/$EPOCH.git # normal git repositories
-- all.git # empty git repo, alternates to git/$EPOCH.git
-- xap$SCHEMA_VERSION/$PART # per-partition Xapian DB
-- xap$SCHEMA_VERSION/over.sqlite3 # OVER-view DB for NNTP and threading
-- msgmap.sqlite3 # same the v1 msgmap
+ foo/ # "foo" is the name of the inbox
+ - inbox.lock # lock file to protect global state
+ - git/$EPOCH.git # normal git repositories
+ - all.git # empty, alternates to $EPOCH.git
+ - xap$SCHEMA_VERSION/$SHARD # per-shard Xapian DB
+ - xap$SCHEMA_VERSION/over.sqlite3 # OVER-view DB for NNTP, threading
+ - msgmap.sqlite3 # same the v1 msgmap
For blob lookups, the reader only needs to open the "all.git"
repository with $GIT_DIR/objects/info/alternates which references
@@ -95,16 +95,16 @@ are documented at:
L
-=head2 XAPIAN PARTITIONS
+=head2 XAPIAN SHARDS
Another second scalability problem in v1 was the inability to
utilize multiple CPU cores for Xapian indexing. This is
-addressed by using partitions in Xapian to perform import
+addressed by using shards in Xapian to perform import
indexing in parallel.
As with git alternates, Xapian natively supports a read-only
interface which transparently abstracts away the knowledge of
-multiple partitions. This allows us to simplify our read-only
+multiple shards. This allows us to simplify our read-only
code paths.
The performance of the storage device is now the bottleneck on
@@ -135,10 +135,10 @@ The overview DB maintains all the header information necessary
to implement the NNTP OVER/XOVER commands and non-search
endpoints of of the PSGI UI.
-In the future, Xapian will become completely optional for v2 (as
-it is for v1) as SQLite turns out to be powerful enough to
-maintain overview information. Most of the PSGI and all of the
-NNTP functionality will be possible with only SQLite in addition
+Xapian has become completely optional for v2 (as it is for v1), but
+SQLite remains required for v2. SQLite turns out to be powerful
+enough to maintain overview information. Most of the PSGI and all
+of the NNTP functionality is possible with only SQLite in addition
to git.
The overview DB was an instrumental piece in maintaining near
@@ -168,7 +168,7 @@ easier. object_id and Message-ID are already known.
=item object_id
The blob identifier git uses (currently SHA-1). No need to
-publically expose this outside of normal git ops (cloning) and
+publicly expose this outside of normal git ops (cloning) and
there's no need to make this searchable. As with v1 of
public-inbox, this is stored as part of the Xapian document so
expensive name lookups can be avoided for document retrieval.
@@ -230,7 +230,7 @@ and testing of the v2 repository format.
=head1 COPYRIGHT
-Copyright 2018-2019 all contributors L
+Copyright 2018-2020 all contributors L
License: AGPL-3.0+ L