Ogg-01184 Expected 4 Bytes But Got 0 Bytes In Trail !new! -

The Oracle GoldenGate error OGG-01184 occurs when a process (typically a Data Pump or Replicat) attempts to read a record from a trail file but encounters an unexpected end-of-file or a corrupted record trailer. Technical Review

The Cause: This error signifies that the process expected a 4-byte record trailer token but found 0 bytes instead. This usually indicates that the trail file was truncated or not fully written—often due to a disk space issue, a network interruption during file transfer, or a source process (Extract) crashing while writing.

The Checkpoint Conflict: You may also see a related error, OGG-01705, which occurs when the process's checkpoint position is actually beyond the physical size of the trail file. Recommended Action Plan

Validate Trail Integrity: Use the Logdump utility to inspect the specific Relative Byte Address (RBA) mentioned in the error. This helps determine if the file is truly empty at that point or just corrupted. Repump or Re-extract:

If the issue is in a remote trail (target side), try deleting the corrupted trail file and restarting the Pump process on the source to re-transmit the data.

If the local trail (source side) is corrupted, you may need to reposition the Extract process to a previous valid sequence number or RBA.

Check System Resources: Verify that the destination disk is not full and that there are no "file handle shortages" on the host system.

Reference Official Support: For detailed recovery steps, Oracle documentation frequently points to Doc ID 1138409.1 on My Oracle Support, which provides specific instructions for handling trail file mismatches. Extract & Pump Abends — oracle-mosc

The error OGG-01184 indicates that an Oracle GoldenGate process (typically a Pump or Replicat) expected to read a specific amount of data (4 bytes) for a record trailer token but found nothing (0 bytes). This usually signifies that the trail file is corrupted or truncated, often due to an interrupted write operation or network failure. Immediate Troubleshooting Steps Identify the Corrupt Trail:

Review the process report file using VIEW REPORT in GGSCI.

Note the trail file name, sequence number (seqno), and Relative Byte Address (RBA) mentioned in the error (e.g., ./dirdat/xx000007 at RBA 246849346). Verify File Integrity with Logdump: Open the Logdump Utility.

Run OPEN and then GOTO .

Use NEXT or SCAN to see if the record is readable. If it fails or shows unexpected data, the file is corrupted. Common Resolutions

Automated Trail Recovery (Preferred for OGG 12.2+):If you are using Oracle GoldenGate 12.2 or higher, you can leverage Automated Remote Trail File Recovery: Stop the Pump process on the source.

Delete the corrupted trail file and all subsequent files in that sequence on the target.

Restart the Pump process. It will automatically detect the missing files and rebuild them from the source trails.

Manual Rollover (If Automation Fails):If the corruption is at the very end of the file, you can force the source process to start a new trail file: On the source, run: ALTER , ETROLLOVER. Note the new sequence number. ogg-01184 expected 4 bytes but got 0 bytes in trail

On the target, run: ALTER , EXTTRAILSOURCE , SEQNEXT.

Repositioning the Process:If you can afford to skip the corrupted record (and handle data loss manually): Find the next valid RBA using Logdump.

Reposition the process: ALTER , RBA . Prevention Tips

Configure Purge Rules: Ensure PURGEOLDEXTRACTS with MINKEEP is configured on the source so trail files aren't deleted before they can be used for recovery.

Network Stability: If this occurs frequently on a Pump process, check for network timeouts or "SSL connection unexpectedly closed" errors in the OCI GoldenGate logs. OGG-01184 - Oracle GoldenGate Error Messages

Action. Contact Oracle Support. The trail file may be corrupted. Oracle Help Center Extract & Pump Abends — oracle-mosc

The Ghost in the Machine: Investigating OGG-01184 The error OGG-01184: Expected 4 bytes, but got 0 bytes, in trail is a classic Oracle GoldenGate "abend" (abnormal end) that usually signals trail file corruption. It occurs when a reader process (like a Pump or Replicat) reaches a point where it expects a specific 4-byte token—typically a record trailer—but finds nothing but an empty void (0 bytes). Common Root Causes

Premature File Termination: The trail file was closed abruptly, often due to a disk full condition, a network glitch during a remote write, or a forced process termination.

Checkpoint Mismatch: The reader's checkpoint position is recorded as being beyond the actual physical end of the file.

Filesystem Corruption: Underlying storage issues or overwriting the OGG installation directory can lead to incomplete data blocks.

Overlapping Extracts: Two Extract groups mistakenly writing to the same trail file name, leading to overwritten and malformed record headers. Troubleshooting and Recovery Strategies

When faced with OGG-01184, the standard action recommended by Oracle is to contact Oracle Support, as the trail may be irrecoverably corrupted. However, seasoned DBAs often use the following manual recovery steps:

Analyze with Logdump:Use the logdump utility to open the failing trail file and navigate to the RBA (Relative Byte Address) mentioned in the error log. This confirms if the record at that position is indeed truncated or invalid.

Repositioning:If the corruption is at the very end of a trail file, you can often "skip" the bad data. Find the last valid LOGBSN or SCN before the error.

Reposition the Primary Extract to that point and perform an ETROLLOVER to start a fresh, clean trail file.

Automated Recovery (OGG 12.2+):Modern versions of GoldenGate include features for Automated Remote Trail File Recovery. In some cases, deleting the corrupted trail file on the target and bouncing the Pump process will trigger an automatic rebuild from the source. The Oracle GoldenGate error OGG-01184 occurs when a

The "Nuclear" Option:If multiple records are corrupted and data integrity is paramount, the safest route is to back up old trails, recreate the Extract and trail groups, and resynchronize the data entirely to ensure no gaps exist. OGG-01184 - Oracle GoldenGate Error Messages

Action. Contact Oracle Support. The trail file may be corrupted. Oracle Help Center OGG-01184 - Oracle GoldenGate Error Messages

Action. Contact Oracle Support. The trail file may be corrupted. Oracle Help Center OGG-01184 - Oracle GoldenGate Error Messages

Action. Contact Oracle Support. The trail file may be corrupted. Oracle Help Center Extract & Pump Abends — oracle-mosc

8. Escalation

If the above fails:

indicates that an Oracle GoldenGate process (typically a ) expected to read 4 bytes for a record trailer but found 0 bytes instead. This usually signifies trail file corruption

or a situation where the reader's checkpoint position is beyond the actual physical end of the file Oracle Communities Immediate Troubleshooting Steps Identify the Point of Failure : Check the report file ( VIEW REPORT

) to find the exact trail file sequence number and Relative Byte Address (RBA) where the error occurred. Verify File Size

: Log into the OS and compare the physical size of the trail file with the RBA reported in the error. If the RBA is larger than the file size, the process is attempting to read non-existent data. Check for Concurrent Writes

: Ensure no other process (e.g., a secondary Extract) is accidentally writing to the same trail file, which can overwrite data and cause corruption. Oracle Communities Resolution Guide Option 1: Repositioning (Most Common Fix)

If the trail file is missing the record trailer (truncated), you may need to skip the corrupted record or reposition the process to the next valid position. Skip to the next RBA ALTER , RBA Use code with caution. Copied to clipboard Reposition by Timestamp

: If the RBA is unknown, move the process back slightly to a known good time and let it re-process (it will skip duplicates automatically if configured correctly). ALTER , BEGIN Use code with caution. Copied to clipboard Option 2: Automatic Trail Recovery (OGG 12.2+ ) If you are on version 12.1.2.1.8 or higher , you can leverage the Automatic Trail Recovery

feature to rebuild the corrupt target trail from the source. Oracle Help Center Stop the process.

Delete the corrupted trail file and any subsequent files in that sequence on the target. Restart the Extract Pump

; it should automatically fetch the missing data from the source trail files. Oracle Help Center Option 3: Manual Trail Regeneration (ETROLLOVER)

If the source trail itself is corrupted, you must force the source Extract to start a new file. www.oracle-scn.com ALTER EXTRACT , ETROLLOVER Extract a logdump snippet of the corrupted trail

This creates a new trail file (e.g., increments sequence from Reposition the Pump to the start of this new sequence: ALTER PUMP , EXTSEQNO , EXTRBA Use code with caution. Copied to clipboard Common Causes to Investigate Network Failures

: Interrupted transfers between source and target can lead to incomplete files. Improper Shutdowns

: Killing OGG processes or OS-level crashes while writing to trails. Disk Space Issues

: Running out of space on the target mount point, preventing the complete writing of record trailers. www.oracle-scn.com GGSCI commands

to verify the current checkpoint RBA versus the actual file size? Extract & Pump Abends — oracle-mosc

The error message you're encountering, "ogg-01184 expected 4 bytes but got 0 bytes in trail," typically occurs in the context of Oracle database operations, particularly when dealing with Oracle Data Pump or Oracle Secure Backup (OSB) operations. However, the most common scenarios involve issues with data files, backups, or exports created with Oracle tools.

What is a GoldenGate Trail File?

Before fixing the error, you must understand what GoldenGate is trying to read. A trail file (e.g., dirdat/rt000001) is a binary sequence of records. Each record represents a database operation (INSERT, UPDATE, DELETE, DDL). The structure is:

| Field | Size | Description | |-------|------|-------------| | Record Length | 4 bytes | Indicates the total size of the following data | | Record Data | Variable | Actual change data in canonical format | | Checksum (optional) | 4 bytes | Integrity check |

The error ogg-01184 expected 4 bytes but got 0 bytes occurs when GoldenGate’s reader reaches a point in the trail file where it expects to read the Record Length header, but the file ends abruptly. The system reads 0 bytes instead of 4.

Impact

Behavior

  1. On OGG page/segment read, verify the trail length against expected length (e.g., header-specified lacing values or codec-specific trailer length).
  2. If expected > available:
    • Return a typed error (e.g., ErrTruncatedTrail expected: u32, got: u32, page_sequence: u64, granule_pos: i64 ) rather than a generic parse error.
    • Include contextual metadata: container offset, page serial, page sequence number, stream/chunk timestamp, and offending packet index.
  3. Provide two configurable recovery modes:
    • Strict (default): fail fast and propagate ErrTruncatedTrail to caller.
    • Recover (best-effort): attempt to continue by:
      • Padding the missing bytes with zeros (or codec-appropriate silence frames) and marking stream as degraded.
      • Skipping the trailing bytes and resynchronizing to next page boundary.
      • Emitting a warning/diagnostic event for downstream players/encoders to decide next steps.
  4. Instrumentation/logging: structured logs/metrics for occurrences (count, file/URL, offset, bytes_missing) and optional callback/hook for host application to collect telemetry.
  5. CLI/Tooling: add a repair tool mode that scans OGG files/streams and either (a) reports all truncated-trail instances, (b) produces a repaired copy using padding/resync, or (c) trims to last good page.
  6. Tests: unit + fuzz tests covering:
    • expected > 0 and got 0
    • partial bytes
    • boundary conditions across page continuations and chained packets
    • behavior under both Strict and Recover modes

3.5 Corruption from Concurrent Access

Rarely, external processes opening the trail file in write mode (e.g., a custom script) can corrupt the binary structure, overwriting the 4-byte headers.

6.1 Monitor Disk Space Proactively

Set up alerts for the trail directory (e.g., 80% full). Use GGSCI info:

GGSCI> INFO EXTRACT *, TASKS
GGSCI> LAG EXTRACT *, REPLICAT *

6.3 Use Reliable File Transfer Protocols

Troubleshooting Steps

  1. Check the trail file size
    ls -l ./dirdat/rt*
    If the last trail file is suspiciously small or ends abruptly, it may be incomplete.

  2. Verify disk space
    df -h — insufficient space can truncate writes.

  3. Check for file corruption
    Use file or head -c 20 to see if the trail contains binary data. A completely empty file is a clear sign.

  4. Review GoldenGate parameter files
    Ensure FORMAT RELEASE is compatible between source and target (if using different OGG versions).