Using the Admin Client or REST API:
oggadmin> INFO CAPTURE <capture_name>
Note the current state (e.g., RUNNING, UNREACHABLE, ERROR).
GGSCI> INFO EXTRACT EXT1
Log output:
ERROR OGG-00446 Unable to read from capture client.
INFO OGG-00999 OGG capture client successfully detached from GoldenGate capture.
(Here detach was a side effect of failure, not a clean stop.)
This message is specific to Integrated Capture mode.
In Classic Capture mode, GoldenGate reads the redo logs directly at the Operating System level. It does not rely on the database's LogMiner server, so you would generally not see this specific "client detached" terminology in Classic Capture setups.
In Integrated Capture, GoldenGate leverages the database engine. The relationship is more intimate. The "detachment" is essentially GoldenGate cleaning up the V$LOGMNR session resources within the Oracle Database SGA (System Global Area).
If you want, I can produce exact ggsci commands and troubleshooting snippets tailored to your GoldenGate version and environment (Oracle DB vs other sources).
The message "OGG Capture client successfully detached from GoldenGate Capture" is a standard informational log entry indicating that a GoldenGate Extract process (the client) has safely disconnected from the database's Logmining Server. What This Means
In an Integrated Capture environment, the Extract process does not read redo logs directly; instead, it "attaches" to a Logmining Server within the Oracle database. This "detached" message typically appears in the database alert logs when the Extract stops normally or is manually shut down using the STOP EXTRACT command. Common Scenarios
Routine Maintenance: You manually issued a STOP EXTRACT command in GGSCI to perform maintenance or update parameters.
Database Shutdown: The database was shut down (e.g., for patching), forcing all attached capture clients to detach as their host server was terminating. Using the Admin Client or REST API: oggadmin>
Process Abend: If this message is preceded by an "ERROR" or "PROCESS ABENDING" in the GoldenGate report file, it means the Extract encountered a critical failure (like a missing log file or permission issue) and detached as part of its failure sequence. Next Steps for Troubleshooting
If this detachment was unintentional, follow these steps to find the root cause:
Check the GoldenGate Report File: Look at the .rpt file for the specific Extract group in the dirrpt directory to see if it recorded an error (e.g., OGG-01668 or OGG-02028) just before detaching.
Verify Database Health: Review the Oracle Database Alert Log for related errors like ORA-03113 (end-of-file on communication channel) or ORA-00600, which would indicate the Logmining server itself crashed.
Check Capture Status: Run select capture_name, state from dba_capture; in the database to see if the underlying capture process is still active or has also stopped. Root Cause for Database Shutdown - Oracle Forums
In Oracle GoldenGate (OGG), the message "OGG Capture Client successfully detached from GoldenGate Capture"
typically appears in the database alert logs or OGG report files when an Integrated Extract process stops
. This confirms a clean shutdown of the handshaking between the OGG Extract process and the database's LogMiner server. Oracle Forums Review of Process Detachment Normal Lifecycle : This is a standard confirmation message during a manual STOP EXTRACT
command or a graceful system shutdown. It indicates that the
server, which mines redo logs for the Extract, has successfully closed its session with the OGG client. Oracle Forums Integrated Architecture
: In Integrated Capture mode, the Extract process does not read redo logs directly; instead, it attaches to a database-level LogMiner server. A "successful detachment" means all Logical Change Records (LCRs) Note the current state (e
currently in the pipeline were processed or safely checkpointed before the connection was severed. www.oracle-scn.com Monitoring Significance
: While usually benign, seeing this message unexpectedly—without a manual stop command—can signal that the OGG process or the underlying database session was killed or terminated by a resource manager. Oracle Blogs Troubleshooting if Unexpected If the detachment occurs frequently or leads to an status, consider these steps: OGG-02028 - Oracle GoldenGate Capture for Oracle 20 Oct 2016 —
GoldenGate Capture: OGG$CAP_PEX00001. setting IGNORE_UNSUPPORTED_TABLE for table (*) Wed Oct 19 08:00:53 2016. GoldenGate Capture: Oracle Forums
Understanding the "OGG Capture Client Successfully Detached" Message In Oracle GoldenGate (OGG), seeing the message "OGG capture client successfully detached from GoldenGate"
in your database alert logs or GoldenGate report files can be alarming, but it is often a routine part of the process lifecycle. The Core Mechanism This message is generated by the
component within the Oracle Database. In an Integrated Capture setup, the GoldenGate Extract process doesn't read the redo logs directly; instead, it acts as a client to a database-level "Capture Server."
When the Extract process stops—whether due to a manual command, a scheduled restart, or an error—it sends a signal to the database to release the resources it was using. The "detachment" is the database confirming that the session between the Extract and the LogMiner engine has been cleanly closed. When It’s Normal You will typically see this message during: Graceful Shutdowns: When you issue STOP EXTRACT Process Restarts: During maintenance windows or configuration changes. Idle Timeouts:
If the Extract is configured to disconnect when no data is being processed.
In these scenarios, the detachment ensures that System Global Area (SGA) memory is freed and that the database doesn't keep a "zombie" capture session active, which could prevent the deletion of old archived logs. When It’s a Problem
If this message appears unexpectedly while the Extract should be running, it indicates an abnormal termination . The detachment is a , not the cause. You should investigate: Extract Abends: $GG_HOME/dirrpt/
file. The Extract may have hit a memory limit or a mapping error. Database Resource Pressure: Log output: ERROR OGG-00446 Unable to read from
If the database instance is low on streams pool memory, it may forcibly detach the client. Network Instability:
In "Downstream Capture" setups, a network flicker between the source and mining databases will trigger a detachment. Conclusion
Think of this message as a "Goodbye" handshake. It confirms the database has successfully cleaned up after a GoldenGate process. If the stop was intentional, the message is proof of a healthy system. If it was unintentional, it serves as the timestamp for when your replication halted, guiding you to look deeper into the Extract’s specific error logs. database alert logs
to see if there was a specific error code paired with this detachment? AI responses may include mistakes. Learn more
In the high-stakes world of real-time data replication, Oracle GoldenGate (OGG) stands as a titan. It powers mission-critical operations like zero-downtime migrations, high-availability setups, and real-time analytics. For administrators managing these environments, the GoldenGate log files are the central nervous system, providing a constant stream of status updates, warnings, and informational messages.
One message that frequently appears in these logs—often causing a momentary heart palpitation for new or even intermediate DBAs—is:
"OGG capture client successfully detached from GoldenGate capture."
Is this a symptom of failure? A hidden warning? Or just noise?
The short answer: It is, in almost all cases, a routine informational message. However, understanding why this message appears, when it appears, and what it implies about your replication architecture is crucial to maintaining a healthy OGG environment.
This article provides a deep dive into the message, its context within Oracle GoldenGate’s architecture (especially for Integrated Capture modes), and the operational scenarios where you can expect to see it.
GGSCI> STOP EXTRACT EXT1
Log output:
INFO OGG-00999 OGG capture client successfully detached from GoldenGate capture.
INFO OGG-00998 Extract EXT1 stopped gracefully.