From 320071d224be031dae2db884a47f6f0f6975f7fb Mon Sep 17 00:00:00 2001 From: Michal Kuratczyk Date: Tue, 14 Jan 2025 20:37:26 +0100 Subject: [PATCH] Remove msg_store_credit_disc_bound I'm fairly sure this setting doesn't change anything in practice and even if it does - I don't think anyone should be teaking it. We'll likely remove it altogether in the future. While at it, add a warning to an old blog post about credit flow. --- .../index.md | 8 ++++++ docs/configure.md | 27 ------------------- versioned_docs/version-4.0/configure.md | 27 ------------------- 3 files changed, 8 insertions(+), 54 deletions(-) diff --git a/blog/2015-10-06-new-credit-flow-settings-on-rabbitmq-3-5-5/index.md b/blog/2015-10-06-new-credit-flow-settings-on-rabbitmq-3-5-5/index.md index a1fe90f8cb..0150031c72 100644 --- a/blog/2015-10-06-new-credit-flow-settings-on-rabbitmq-3-5-5/index.md +++ b/blog/2015-10-06-new-credit-flow-settings-on-rabbitmq-3-5-5/index.md @@ -4,6 +4,14 @@ tags: ["Performance", ] authors: [alvaro] --- +:::warning +This blog post was written for RabbitMQ 3.5, released in 2015. While some parts still +apply, there's a lot of outdated information. For example, RabbitMQ 4.0 +doesn't support queue mirroring anymore and "paging messages to disk" is +no longer something that RabbitMQ has to do, since messages are almost +always persisted to disk right away. +::: + In order to prevent fast publishers from overflowing the broker with more messages than it can handle at any particular moment, RabbitMQ implements an internal mechanism called *credit flow* that will be diff --git a/docs/configure.md b/docs/configure.md index 6da397875f..4a148b677c 100644 --- a/docs/configure.md +++ b/docs/configure.md @@ -1438,33 +1438,6 @@ under the `rabbit` section.

- - `msg_store_credit_disc_bound` - - The credits that a queue process is given by the message store. -

- By default, a queue process is given 4000 message store credits, and then 800 for every 800 messages that it processes. -

-

- Messages which need to be paged out due to memory pressure will also use this credit. -

-

- The Message Store is the last component in the credit flow chain. [Learn about credit flow](/blog/2015/10/06/new-credit-flow-settings-on-rabbitmq-3-5-5). -

-

- This value only takes effect when messages are persisted to the message store. - If messages are embedded on the queue index, then modifying this setting has no effect because credit_flow is NOT used when writing to the queue index. -

-

- Default: -```erlang -{rabbit, [ -{msg_store_credit_disc_bound, {4000, 800}} -]} -``` -

- - `queue_index_max_journal_entries` diff --git a/versioned_docs/version-4.0/configure.md b/versioned_docs/version-4.0/configure.md index 218dee5de6..4bf1d9bfcf 100644 --- a/versioned_docs/version-4.0/configure.md +++ b/versioned_docs/version-4.0/configure.md @@ -1438,33 +1438,6 @@ under the `rabbit` section.

- - `msg_store_credit_disc_bound` - - The credits that a queue process is given by the message store. -

- By default, a queue process is given 4000 message store credits, and then 800 for every 800 messages that it processes. -

-

- Messages which need to be paged out due to memory pressure will also use this credit. -

-

- The Message Store is the last component in the credit flow chain. [Learn about credit flow](/blog/2015/10/06/new-credit-flow-settings-on-rabbitmq-3-5-5). -

-

- This value only takes effect when messages are persisted to the message store. - If messages are embedded on the queue index, then modifying this setting has no effect because credit_flow is NOT used when writing to the queue index. -

-

- Default: -```erlang -{rabbit, [ -{msg_store_credit_disc_bound, {4000, 800}} -]} -``` -

- - `queue_index_max_journal_entries`