Ogg Capture Client Successfully Detached From Goldengate Capture Fix May 2026
Understanding the "OGG Capture Client Successfully Detached from GoldenGate Capture" Message
In the world of Oracle GoldenGate (OGG), log messages are the primary window into the health and status of your data replication environment. One message that frequently appears in the Oracle alert logs and GoldenGate process logs is: "OGG capture client successfully detached from GoldenGate capture."
While this message sounds like a technical failure at first glance, it is often a routine part of the GoldenGate lifecycle. This article explores what this message means, why it occurs, and when you should actually be concerned. What Does This Message Mean?
Oracle GoldenGate uses an Extract process to capture changes from the source database. In modern "Integrated Capture" modes, the Extract process acts as a client to a specialized background process within the Oracle Database known as the LogMiner Capture process.
When you see the message "OGG capture client successfully detached," it indicates that the Extract process (the client) has gracefully severed its connection with the database’s capture engine.
Essentially, the database is acknowledging that the GoldenGate process has stopped requesting data and the session has been closed cleanly. Common Scenarios Where This Occurs
In most cases, this message is a confirmation of a successful administrative action rather than an error. Here are the most common triggers: 1. Manual Stopping of the Extract
If an administrator issues the STOP EXTRACT command in GGSCI or the Admin Client, the process will finish its current work and detach from the database. The database then logs this detachment to confirm the resources have been released. 2. Extract Process Restart
When you restart an Extract, it must first shut down the old session. You will see a "detached" message for the stopping process, followed shortly by a "bound" or "attached" message for the new process. 3. Network or Timeout Issues
If there is a brief network flicker between the GoldenGate hub and the database server, the client might detach. If GoldenGate is configured with AUTORESTART, it may reconnect so quickly that you only notice the detachment message in the logs. 4. Database Maintenance
If the source database is being shut down or put into a state where the LogMiner server is no longer available, the GoldenGate client will be forced to detach. Is it an Error? How to Tell.
To determine if this message requires action, you must look at the context of the logs. Situation A: Normal (No Action Required)
Log Sequence: You see "Stopping Extract," followed by "Successfully detached," followed by the process status showing as STOPPED. Reason: This is a standard clean shutdown. Situation B: Critical (Action Required)
Log Sequence: You see "Successfully detached," followed immediately by ERROR OGG-00664 or OGG-01031, and the process status shows as ABENDED. It confirms that cleanup succeeded
Reason: This implies the detachment was involuntary. Something—like a database crash, a memory exhaustion issue (SGA/Streams Pool), or a permissions change—forced the client off. Troubleshooting Forced Detachments
If your Extract is abending (crashing) with this message, follow these steps:
Check the Database Alert Log: The source database often has more information. Look for ORA-errors (like ORA-01341: LogMiner out of memory) occurring at the exact same timestamp.
Verify Streams Pool: Integrated Capture lives in the Streams Pool. If the STREAMS_POOL_SIZE is too small, the database may kick the GoldenGate client to save system stability.
Check Extract Long-Running Transactions: A single massive transaction can cause the capture client to struggle. Use SEND EXTRACT to see if a specific transaction is causing a bottleneck.
Review Patch Levels: Detachment issues are occasionally linked to bugs in the LogMiner engine. Ensure both your GoldenGate home and your Oracle Database have the latest "Database Release Update" (RU).
The message "OGG capture client successfully detached from GoldenGate capture" is, by itself, a sign of a healthy, communicative relationship between GoldenGate and the Oracle Database. It confirms that the session ended without leaving "zombie" processes or orphaned locks in the database.
However, if you see this message appearing repeatedly or accompanied by an ABENDED status, it is a red flag to investigate your database’s Streams Pool memory and LogMiner health.
Understanding the "OGG Capture Client Successfully Detached" Message
In the world of Oracle GoldenGate (OGG), log messages are the primary window into the health and status of your data replication environment. One message that often appears in the ggserr.log—and occasionally causes confusion for administrators—is:
"OGG capture client successfully detached from GoldenGate capture."
While this message sounds like a failure notification, it is actually a standard operational status update. This article explores what this message means, why it occurs, and how to troubleshoot it if it happens unexpectedly. What Does This Message Mean?
Oracle GoldenGate uses a "Capture" process (also known as Extract) to pull changed data from source database transaction logs. To do this efficiently, especially in Integrated Capture mode, the OGG Extract process registers as a client with the database’s logmining server. Verdict: Expected behavior. No action required.
The "detached" message signifies that the communication link between the GoldenGate Extract process and the underlying database capture engine has been cleanly severed. In simpler terms, the client (GoldenGate) told the server (the Database) it was finished, and the database acknowledged the disconnection. Common Scenarios for This Message 1. Graceful Shutdown
The most common reason you see this message is a manual stop of the Extract process. When you issue the command STOP EXTRACT in GGSCI or Admin Client, the process finishes its current task and sends a detachment signal to the database to release resources. 2. Process Restart or Re-initialization
If you change an Extract configuration and restart the process, it must detach from the old session before attaching to a new one. You will see the detachment message followed shortly by an "attached" message. 3. Heartbeat and Timeout Events
In some Integrated Capture environments, if there is a long period of inactivity or a network "hiccup" between the GoldenGate instance and the database instance, the capture client may temporarily detach and reattach to refresh the session. 4. Extract Abends (Crashes)
While the message says "successfully detached," it can sometimes appear during a crash. If the Extract hits a critical error (an "Abend"), it may still attempt to run its cleanup routines, which includes detaching from the database before the process terminates. Is This an Error?
Usually, no. If you see this message in conjunction with a STOP command you initiated, it is a sign that GoldenGate is working exactly as intended. It confirms that the database has successfully reclaimed the memory and processes (Logminers) dedicated to that Extract. However, it is a red flag if:
The message appears while the Extract status is still supposed to be RUNNING.
The message is immediately followed by an ERROR or ABENDING status in the report file.
It happens repeatedly (looping), preventing data from flowing. Troubleshooting Unexpected Detachments
If your Capture client is detaching without your instruction, follow these steps to find the root cause: 1. Check the Extract Report File
Navigate to your dirrpt directory and open the .rpt file for the specific Extract. Look for the lines immediately preceding the detachment. Often, a database-level error (like an ORA- error) is the true culprit. 2. Review the Database Alert Log
Since Integrated Capture runs "inside" the database, the source database's alert log often contains the real reason for the disconnect. Look for issues related to:
Streams Pool Size: If the STREAMS_POOL_SIZE is too small, the logminer may force a detachment. Logminer Errors: Look for ORA-01280 or similar errors. 3. Verify Extract Checkpoints everything is functioning as designed.
Use INFO EXTRACT to see if the Extract is stuck on a specific SCN (System Change Number). If it cannot find a required archived log, it may detach and wait. 4. Check Network Stability
If the GoldenGate process is running on a different server than the database (Downstream Capture), ensure the SQL*Net connection is stable. Network timeouts can cause the capture client to drop the connection.
The message "OGG capture client successfully detached from GoldenGate capture" is a confirmation of a clean break between GoldenGate and the Oracle Database. In the vast majority of cases, it is a healthy part of the process lifecycle. Only when it is accompanied by an "Abended" status should you dive into the report files and database logs to investigate further.
3. Is It an Error or Warning?
No. It is an informational message with severity level INFO.
- It confirms that cleanup succeeded.
- You should not see this unless something intentionally disconnected.
- If you see it unexpectedly, check if someone restarted GoldenGate or stopped an Extract without your knowledge.
1. Set Appropriate IDLETIMEOUT Values
Do not set IDLETIMEOUT 0 (disabled) for all extracts. For low-volume systems, set a reasonable timeout (e.g., 30-60 minutes) to allow clean detachment and resource release.
Step 3: Check the Database Alert Log
Since the internal Capture process resides in the database, query its status:
SELECT CAPTURE_NAME, STATUS, ERROR FROM DBA_CAPTURE;
If the capture process shows ABORTED or ERROR, the detachment was forced.
7. Related Messages
| Message ID | Text | |------------|------| | OGG-00998 | Capture client failed to attach | | OGG-00999 | Capture client detached (this message) | | OGG-00446 | Network read failure (often precedes detach) | | OGG-01296 | Capture client process died unexpectedly |
What Does "Successfully Detached" Mean?
This message confirms that the Capture Client has severed its connection to the database's log mining facility. This involves:
- Releasing locks held on database resources or log files.
- Closing the internal database cursor used for reading transactions.
- Flushing the current read position to the OGG Checkpoint file.
Step-by-Step: Successful Detachment
When Should You Worry?
You should only be concerned if the message indicates a failure. For example:
- "OGG capture client failed to detach"
- Or, if you see the "successfully detached" message, but the process immediately abends (crashes) afterwards without a clean shutdown command from you.
If the process continues to run (status shows "RUNNING") after this message, or if the message appears during a manual STOP command, everything is functioning as designed.
Scenario 1: Graceful Shutdown (Good)
This is the most common and benign cause. When you issue a STOP EXTRACT command, the Extract process performs a sequence of cleanup activities:
- It stops reading new LCRs.
- It writes a final checkpoint.
- It sends a disconnect signal to the database’s internal Capture process.
- Log message:
OGG capture client successfully detached from GoldenGate capture.
Verdict: Expected behavior. No action required.