Release Notes

The new Analytics tab in the SymmetricDS Pro console provides five pre-built reports that give operations teams deep visibility into replication activity and health.

Reports are generated by the Refresh Analytics job, which runs every six hours by default. Each report screen shows when data was last refreshed and provides a Run Now button to trigger the job immediately. The Data retained for link shows the current retention period and opens a dialog to edit the purge.stats.retention.minutes parameter.

Table Heat Map — shows the total rows synchronized per table per day over a rolling window of up to 30 days. Cell colors indicate activity levels relative to other tables. Filters control the time range, the event type (insert, update, or delete), the metric (sent or loaded), and the number of tables shown.

Table Status Report — displays the insert, update, and delete activity for a single table over a rolling window. Includes an event-type donut chart, a stacked daily bar chart, and a daily breakdown table. Tables with significantly above-average activity are flagged with a HIGH ACTIVITY badge. Click a table name in the Table Heat Map to navigate directly to its Table Status Report.

Capture Health — shows whether CDC was actively capturing changes for each configured table, month by month, over a 13-month rolling window. Green cells indicate continuous active capture; yellow cells indicate configuration changes; orange cells indicate a partial capture gap; red cells indicate no capture for the entire month. Clicking a cell opens a detail dialog showing rebuild events or exact gap periods.

Node Backlog Heat Map — shows the average outgoing batch backlog per node per day. Summary cards surface the node with the largest current backlog and the node whose backlog is growing fastest. When offline nodes collectively hold 50% or more of the total backlog, a warning message identifies those nodes as a potential indicator of network trouble.

Cluster Traffic Heat Map — shows how replication traffic is distributed across cluster hosts per day, relative to the cluster average. An imbalance callout identifies hosts consistently handling more or less than their expected share of traffic. Filter by replication stage (Routed, Extracted, Sent, or Loaded), channel, and row or byte count.

SymmetricDS 3.18 expands Data Refresh to support multiple, independently scheduled refresh jobs and extends replication to database views.

The Deploy Wizard automatically presents the new Data Refresh Configuration screen whenever the deployment includes tables or views that cannot use CDC — such as views, tables without primary keys on log-based SQL Server sources, or tables without compatible timestamp columns on time-based sources. Each CDC-ineligible table or view must be assigned a reload strategy and a schedule before the wizard can proceed. Predefined schedules such as hourly, daily, and weekly are available, and custom schedules can be created inline by selecting + Create New Schedule…​.

For post-deployment management, named Data Refresh jobs can be created and edited under Configure → Details → Jobs. Tables are assigned to a specific job using the Data Refresh Job field in Configure → Details → Table Routing. Tables configured for CDC remain on the default CDC assignment and are unaffected by any refresh job.

The Data Refresh Type field in Configure → Details → Table Routing controls how each table is refreshed when its assigned job runs:

Views are now supported in replication on Microsoft SQL Server, Oracle, PostgreSQL, MySQL, and MariaDB source endpoints. The Configure Diagram’s Select Tables screen includes a Show Views checkbox to include views during setup.

The official SymmetricDS Pro Docker image now runs as the symds non-root system account (UID 1000 by default), satisfying Kubernetes security policies such as runAsNonRoot: true. Named volumes work without additional configuration; bind mounts require the host directory to be writable by the container UID. To use a different UID, pass the SYMDS_UID build argument at image build time.

A hardened image variant is available under the -hardened tag suffix (for example, jumpmind/symmetricds-pro:3.18.0-hardened). The hardened image uses a JRE-only base image to exclude the Java compiler toolchain and removes the Alpine package manager to reduce the post-compromise attack surface. Features that compile Java at runtime — Java jobs, Java routers, Java transforms, and Java extensions — are not available in the hardened image; use BeanShell scripting as an alternative for these features.

The hardened image supports running with all Linux capabilities dropped:

In Kubernetes, the equivalent security context is:

Each hardened image includes an SBOM attestation verifiable via cosign for supply chain auditing and provenance verification.

SymmetricDS now publishes its built-in metrics through the OpenTelemetry (OTel) API, making them available to any OTel-compatible observability platform — including Prometheus (via the OTLP receiver), Grafana Cloud, DataDog, and Dynatrace.

Two integration modes are supported. When no global OpenTelemetry instance is present in the JVM, SymmetricDS initializes its own SDK using standard OTel autoconfiguration; exporters and other settings are controlled by OTEL_* environment variables (for example, OTEL_EXPORTER_OTLP_ENDPOINT or OTEL_METRICS_EXPORTER). When an OTel Java agent is attached to the JVM, SymmetricDS detects the existing registered instance and routes all metrics through it automatically — no additional SDK configuration is required.

The metrics.opentelemetry.enabled parameter provides per-engine control and overrides the server-level OTEL_SDK_DISABLED flag for a single engine. This allows a server hosting multiple engines to enable or disable OTel publishing independently per engine.

SymmetricDS 3.18 introduces a built-in metrics framework that continuously collects and stores detailed statistics about the synchronization pipeline. Observations are aggregated into five-minute time windows and stored as summary statistics — average, minimum, maximum, standard deviation, and count — across four new tables: METRIC_KEY, METRIC_CONTEXT, METRIC_STATS_FLOAT64, and METRIC_STATS_INT64.

The following categories of metrics are collected automatically:

Metrics are published via the OpenTelemetry API under the scope symmetricds and are used to power the Analytics reports in SymmetricDS Pro.

SymmetricDS 3.18 adds first-class container support via the bin/sym --container command. This mode runs SymmetricDS as PID 1 inside the container, enabling proper signal handling and graceful shutdown behavior expected by container orchestrators.

Two HTTP health endpoints are available for container orchestrators:

/health/liveliness — returns HTTP 200 with the following body when SymmetricDS is running:

/health/readiness — returns per-engine readiness status. When all engines are ready, it returns HTTP 200; when any engine is not ready, it returns HTTP 503: