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

The alert came in at 03:00 AM. The critical Extract process, EXT_PROD, was in an ABENDED state. The report file pointed to a specific line in the GoldenGate trail file, let's call it /ggs/dirdat/ea000123.

The error log was stark:

OGG-01184: Expected 4 bytes but got 0 bytes in trail /ggs/dirdat/ea000123. ogg-01184 expected 4 bytes but got 0 bytes in trail

To the uninitiated, this looks like a generic I/O failure. To a GoldenGate administrator, this is a specific narrative of interrupted transmission. GoldenGate trail files are binary, sequential files. They are written in blocks. Every record written to a trail file includes a header. In this context, the "4 bytes" refers to the record length indicator or the standard record header that the process expects to read to determine how much data follows.

When the Extract process reads a trail, it acts like a strict parser. It reads the first 4 bytes to say, "Okay, the next block of data is X size." In this case, the process moved the file pointer to a specific offset, reached out to grab the 4-byte header, and grasped nothing. It hit the End of File (EOF) marker prematurely. The alert came in at 03:00 AM

Create a daily logdump validator:

#!/bin/bash
for trail in /u01/gg/dirdat/rt*; do
  echo "checking $trail"
  echo "open $trail" > /tmp/logdump_cmd
  echo "n" >> /tmp/logdump_cmd
  echo "q" >> /tmp/logdump_cmd
  /u01/gg/logdump < /tmp/logdump_cmd | grep -i "error\|corrupt\|unexpected"
done

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: OGG-01184: Expected 4 bytes but got 0 bytes

| 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.

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