[BUG] PostgreSQL 14.5: Data corruption in table tb_workstation_message (possible fstrim-related on eMMC)

To: pgsql-bugs@postgresql.org

Subject: [BUG] PostgreSQL 14.5: Data corruption in table tb_workstation_message (possible fstrim-related on eMMC)

Environment Information

PostgreSQL Version: 14.5

OS: Debian GNU/Linux 11 (bullseye)

Architecture: aarch64 (8-core CPU)

Memory: 8GB

Storage Medium: eMMC

Problem Description
Data corruption occurred in the tb_workstation_message table (record guid: ce04bd3f-232d-4c7f-9a91-540d0e581649). Queries targeting this record fail with:

plaintext



ERROR: invalid memory alloc request size 18446744073709551613 





Corruption details of the record:


Only the guid field remains valid;

All int-type fields (e.g., upload_status) are set to 0;

All timestamp-type fields (e.g., create_time) are reset to 2000-01-01 00:00:00;

String-type fields (e.g., operator, content) are inaccessible (queryable only after forcing UPDATE to null).

Timeline

Record insertion: 2025-11-25 21:23:51

Last modification: 2025-11-27 09:41:10

Anomaly window: 2025-12-01 03:00:00 ~ 09:02:31 (record was intact before 03:00:00)

First error detected: 2025-12-01 09:02:31 (triggered by a 30s-interval business cron job querying upload_status = 0)

Error Output (Query Example)
sql



postgres=# select * from tb_workstation_message where guid = 'ce04bd3f-232d-4c7f-9a91-540d0e581649'; ERROR:  invalid memory alloc request size 18446744073709551613 





Investigation Details

Database Logs: No output between 2025-12-01 05:37:05.932 ~ 09:02:31.533 (no abnormalities found).

Dynamic Library Check: libpq.so had environment variable misconfiguration (not pointing to PG install dir), but the business app does NOT depend on this library — low corruption probability.

eMMC Storage Analysis:

Used dd to extract the corrupted block; hex analysis shows only guid bytes are valid (others are 0, confirming physical data corruption).

fstrim Check:

fstrim executed at 2025-12-01 00:27 (asynchronous, runs on disk idle); anomaly occurred after this.

Reproduction attempt: Simulated data insertion + 10+ fstrim runs — corruption not reproduced.

Impact

Business failure: Query errors trigger business alerts.

Backup failure: Database backups are affected by corrupted data.

Additional Notes

No system/app/PG restarts during the anomaly window.

No writes to tb_workstation_message after 2025-12-01 05:34:00.

No online operations/terminals between 05:34:00 ~ 09:02:31.

Request:

We suspect this may relate to fstrim on eMMC (with PG 14.5) but cannot reproduce it. Could the community help analyze the root cause, or guide further troubleshooting?






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