pgref.dev/sqlite/errors/SQLITE_IOERR_SHMOPEN
SQLITE_IOERR_SHMOPENERRORTier 2 — Caution⚠️ MEDIUM confidence

I/O error opening WAL shared-memory file

Category: I/O ErrorVersions: 3.7.0+

🔴 Production Risk Error

High — WAL-mode reads will fail without -shm.

What this means

SQLITE_IOERR_SHMOPEN (4618) is returned when SQLite cannot open the WAL shared-memory (-shm) file. Without the -shm file WAL-mode readers cannot function.

Why it happens

  1. 1Insufficient permissions to create the -shm file in the database directory.
  2. 2Disk full preventing -shm file creation.
  3. 3Filesystem does not allow new file creation.

How to reproduce

WAL-mode database open when the -shm file cannot be created or opened.

trigger — this will ERROR
# ls -la /path/to/database/  # check write permission on directory
# df -h /path/to/database/   # check disk space
sqlite3.OperationalError: disk I/O error

Fix 1

Why this works

Grant write permission on the database directory to the application user.

Fix 2

Why this works

Free disk space if the filesystem is full.

Sources

📚 Official docs: https://www.sqlite.org/rescode.html#ioerr_shmopen

🔧 Source ref: sqlite3.h — SQLITE_IOERR_SHMOPEN = 4618

Confidence assessment

⚠️ MEDIUM confidence

Stable.

See also

⚙️ This error reference was generated with AI assistance and reviewed for accuracy. Examples are provided to illustrate common scenarios and may not cover every case. Always test fixes in a development environment before applying to production. Spotted an error? Suggest a correction →