Topology process neo4j running out of memory after upgrade to 25.4.9
Article ID: 449893
Updated On:
Products
Issue/Introduction
The topology synch is not completing.
The neo4j service is stopping or restarting
We see these messages in the
- /opt/netops-topology/neo4j/logs/neo4j.log
2026-07-14 10:51:59.368+0000 ERROR Client triggered an unexpected error [Neo.DatabaseError.Transaction.TransactionStartFailed]: The database has encountered a critical error, and needs to be restarted. Please see database logs for more details., reference 60ce2652-b7cf-4020-9964-96aecf6e9c1f.
2026-07-14 10:51:59.370+0000 INFO [neo4j/6f3d59a8] Transaction rolled back
2026-07-14 10:52:00.821+0000 ERROR [neo4j/6f3d59a8] Panic detected [Reason: Kernel database panicked, Error: org.neo4j.internal.kernel.api.exceptions.TransactionApplyKernelException: Failed to apply transaction: Transaction #508737 {started 2026-07-14 10:42:41.261+0000, committed 2026-07-14 10:42:42.794+0000, with 7 commands in this transaction, lease -1, latest committed transaction id when started was 508731, consensusIndex: -1}]
Caused by: java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space
We see these messages in the
- /opt/netops-topology/neo4j/logs/debug.log
2026-07-14 18:59:03.450+0000 WARN [o.n.b.p.c.f.r.NetworkResponseHandler] Unable to send error back to the client. null
io.netty.channel.StacklessClosedChannelException: null
at io.netty.channel.AbstractChannel$AbstractUnsafe.write(Object, ChannelPromise)(Unknown Source) ~[netty-transport-4.1.111.Final.jar:4.1.111.Final]
Suppressed: java.lang.OutOfMemoryError: Java heap space
2026-07-14 18:59:03.450+0000 ERROR [o.n.m.DatabaseHealth] [neo4j/6f3d59a8] Database panic: The database has encountered a critical error, and needs to be restarted. Please see database logs for more details.
Caused by: java.util.concurrent.ExecutionException: java.lang.OutOfMemoryError: Java heap space
Environment
DX NetOps 25.4.9
Topology 25.4.9
Cause
Topology utilizes Source Address Tables (SAT) as a mechanism for determining Layer 2 connectivity, particularly when other protocols like CDP or LLDP are unavailable.
Some of the current DB queries need to be optimized for better performance.
Resolution
Disable the SAT protocol under advanced options in all Performance Management discovery profiles.
Additional Information
Defect DE209744 has been opened to fix this in a future build.
SAT is a protocol used during network discovery to resolve Layer 2 topology. It allows DX NetOps to map physical connections between devices by analyzing the learned neighbor MAC addresses stored in a switch's source address table.
- Version Note: Enhanced SAT-based connection resolution was introduced in version 25.4.2.
- Usage: It is typically used in conjunction with other discovery protocols such as CDP (Cisco Discovery Protocol), LLDP (Link Layer Discovery Protocol), and ARP (Address Resolution Protocol).
- Functionality: When enabled in a discovery profile, the Data Aggregator uses SAT data to accurately map device connections, such as linking "pingable" nodes (like servers or printers) to specific switch ports.
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