user/dev discussion of public-inbox itself
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From: Eric Wong <>
Subject: [PATCH] doc: expand on indexBatchSize regarding fragementation
Date: Mon, 31 Aug 2020 04:33:37 +0000
Message-ID: <> (raw)

And change the documentation reference in -tuning to
point to the -index manpage while we're at it.
 Documentation/public-inbox-index.pod  | 5 +++--
 Documentation/public-inbox-tuning.pod | 6 ++++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/Documentation/public-inbox-index.pod b/Documentation/public-inbox-index.pod
index 207b2ed8..936516f8 100644
--- a/Documentation/public-inbox-index.pod
+++ b/Documentation/public-inbox-index.pod
@@ -129,8 +129,9 @@ below.
 When using rotational storage but abundant RAM, using a large
 value (e.g. C<500m>) with C<--sequential-shard> can
-significantly speed up the initial index and full C<--reindex>
-invocations (but not incremental updates).
+significantly speed up and reduce fragmentation during the
+initial index and full C<--reindex> invocations (but not
+incremental updates).
 Available in public-inbox 1.6.0 (PENDING).
diff --git a/Documentation/public-inbox-tuning.pod b/Documentation/public-inbox-tuning.pod
index b4e7698b..f5a25676 100644
--- a/Documentation/public-inbox-tuning.pod
+++ b/Documentation/public-inbox-tuning.pod
@@ -74,7 +74,7 @@ sharding imposes a performance penalty for read-only queries.
 Users with large amounts of RAM are advised to set a large value
 for C<publicinbox.indexBatchSize> as documented in
 C<dm-crypt> users on Linux 4.0+ are advised to try the
 C<--perf-same_cpu_crypt> C<--perf-submit_from_crypt_cpus>
@@ -95,7 +95,9 @@ Disabling copy-on-write also disables checksumming, thus C<raid1>
 Fortunately, these SQLite and Xapian indices are designed to
 recoverable from git if missing.
-Disabling CoW does not prevent all fragmentation.
+Disabling CoW does not prevent all fragmentation.  Large values
+of C<publicInbox.indexBatchSize> also limit fragmentation during
+the initial index.
 Avoid snapshotting subvolumes containing Xapian and/or SQLite indices.
 Snapshots use CoW despite our efforts to disable it, resulting

             reply	other threads:[~2020-08-31  4:33 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-31  4:33 Eric Wong [this message]
2020-08-31 23:43 ` [PATCH] doc: expand on indexBatchSize regarding fragmentation Eric Wong

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