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update MySQL core sequencer support #22929

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276dc74
update MySQL core sequencer support
bsanchez-the-roach Mar 2, 2026
88ec0ac
added replication pipeline metrics
bsanchez-the-roach Mar 3, 2026
63393aa
fixed link
bsanchez-the-roach Mar 3, 2026
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Binary file added src/current/images/molt/replicator-metrics-1.png
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@bsanchez-the-roach bsanchez-the-roach Mar 3, 2026 •
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I've included this diagram in the PR for now, even though it's not currently being included on the Replicator Metrics page. I want to see how a reviewer from the Migrations team feels about using source-specific diagrams instead (see the current deploy preview, toggle through the different source buttons on the page). My argument for that is that there's nowhere else on the page where we expect a user to be concerned with another source's metrics, so why should we start now?

That being said, if you insist that this would be useful, I'll concede to your greater knowledge of what a MOLT user needs to know, and will include this as is.

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I think it will be useful, but we don't want to put it in the more "practical" part of our notes. Instead, I think we should put this as a sub-page or a deeper dive for concepts.

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31 changes: 20 additions & 11 deletions src/current/molt/replicator-metrics.md
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Expand Up @@ -35,14 +35,10 @@ This page describes and provides usage guidelines for Replicator metrics, accord
- [**Staging**](#staging): Buffers mutations for ordered processing and crash recovery.
</section>

<section class="filter-content" markdown="1" data-scope="postgres oracle cockroachdb">
<section class="filter-content" markdown="1" data-scope="postgres mysql oracle cockroachdb">
- [**Core sequencer**](#core-sequencer): Processes staged mutations, maintains ordering guarantees, and coordinates transaction application.
</section>

<section class="filter-content" markdown="1" data-scope="mysql">
- **Core sequencer**: Processes staged mutations, maintains ordering guarantees, and coordinates transaction application.
</section>

- [**Target apply**](#target-apply): Applies mutations to the target database.

## Set up metrics
Expand Down Expand Up @@ -91,7 +87,7 @@ Use the Replicator Grafana dashboard [bundled with your binary]({% link molt/mol
</section>

<section class="filter-content" markdown="1" data-scope="oracle">
Use the Replicator Grafana dashboards [bundled with your binary]({% link molt/molt-replicator.md %}#installation) to visualize metrics. The general Replicator dashboard (`replicator_grafana_dashboard.json`) displays overall replication metrics, and the Oracle-specific dashboard (`replicator_oracle_grafana_dashboard.json`) displays [Oracle source metrics](#oracle-source). The bundled dashboards match your binary version. Alternatively, you can download the latest dashboards for [Replicator](https://replicator.cockroachdb.com/replicator_grafana_dashboard.json) and [Oracle source metrics](https://replicator.cockroachdb.com/replicator_oracle_grafana_dashboard.json).
Use the Replicator Grafana dashboards [bundled with your binary]({% link molt/molt-replicator.md %}#installation) to visualize metrics. The general Replicator dashboard (`replicator_grafana_dashboard.json`) displays overall replication metrics, and the Oracle-specific dashboard (`replicator_oracle_grafana_dashboard.json`) displays [Oracle source metrics](#source-read). The bundled dashboards match your binary version. Alternatively, you can download the latest dashboards for [Replicator](https://replicator.cockroachdb.com/replicator_grafana_dashboard.json) and [Oracle source metrics](https://replicator.cockroachdb.com/replicator_oracle_grafana_dashboard.json).
</section>

## Overall replication metrics
Expand Down Expand Up @@ -152,12 +148,28 @@ Monitor the following metrics to track checkpoint progress:

## Replication pipeline metrics

<section class="filter-content" markdown="1" data-scope="postgres">
<img src="{{ 'images/molt/replicator-metrics-pg.png' | relative_url }}" alt="Single Region MAZ" style="border:0px solid #eee;max-width:80%;margin:auto;display:block" />
</section>

<section class="filter-content" markdown="1" data-scope="mysql">
<img src="{{ 'images/molt/replicator-metrics-mysql.png' | relative_url }}" alt="Single Region MAZ" style="border:0px solid #eee;max-width:80%;margin:auto;display:block" />
</section>

<section class="filter-content" markdown="1" data-scope="oracle">
<img src="{{ 'images/molt/replicator-metrics-oracle.png' | relative_url }}" alt="Single Region MAZ" style="border:0px solid #eee;max-width:80%;margin:auto;display:block" />
</section>

<section class="filter-content" markdown="1" data-scope="cockroachdb">
<img src="{{ 'images/molt/replicator-metrics-crdb.png' | relative_url }}" alt="Single Region MAZ" style="border:0px solid #eee;max-width:80%;margin:auto;display:block" />
</section>


### Source read

[Source read](#replication-pipeline) metrics track the health of connections to source databases and the volume of incoming changes.

<section class="filter-content" markdown="1" data-scope="cockroachdb">
#### CockroachDB source

- `checkpoint_committed_age_seconds`
- Description: Age of the committed checkpoint.
Expand All @@ -174,7 +186,6 @@ Monitor the following metrics to track checkpoint progress:
</section>

<section class="filter-content" markdown="1" data-scope="oracle">
#### Oracle source

{{site.data.alerts.callout_success}}
To visualize the following metrics, import the Oracle Grafana dashboard [bundled with your binary]({% link molt/molt-replicator.md %}#installation) (`replicator_oracle_grafana_dashboard.json`). The bundled dashboard matches your binary version. Alternatively, you can download the [latest dashboard](https://replicator.cockroachdb.com/replicator_oracle_grafana_dashboard.json).
Expand Down Expand Up @@ -207,7 +218,6 @@ To visualize the following metrics, import the Oracle Grafana dashboard [bundled
</section>

<section class="filter-content" markdown="1" data-scope="mysql">
#### MySQL source

- `mylogical_dial_success_total`
- Description: Number of times Replicator successfully started logical replication.
Expand All @@ -221,7 +231,6 @@ To visualize the following metrics, import the Oracle Grafana dashboard [bundled
</section>

<section class="filter-content" markdown="1" data-scope="postgres">
#### PostgreSQL source

- `pglogical_dial_success_total`
- Description: Number of times Replicator successfully started logical replication (executed `START_REPLICATION` command).
Expand Down Expand Up @@ -254,7 +263,7 @@ For checkpoint terminology, refer to the [MOLT Replicator documentation]({% link
- Interpretation: High values indicate write performance issues on the staging database.
</section>

<section class="filter-content" markdown="1" data-scope="postgres oracle cockroachdb">
<section class="filter-content" markdown="1" data-scope="postgres mysql oracle cockroachdb">
### Core sequencer

[Core sequencer](#replication-pipeline) metrics track mutation processing, ordering, and transaction coordination.
Expand Down
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