SQLite3 database or disk is full / the database disk image is malformed

I use the following script for repairing malformed sqlite files:

#!/bin/bash

cat <( sqlite3 "$1" .dump | grep "^ROLLBACK" -v ) <( echo "COMMIT;" ) | sqlite3 "fix_$1"

Most of the time when a sqlite database is malformed it is still possible to make a dump. This dump is basically a lot of SQL statements that rebuild the database.

Some rows might be missing from the dump (probably becasue they are corrupted). If this is the case the INSERT statements of the missing rows will be replaced with some comments and the script will end with a ROLLBACK TRANSACTION.

So what we do here is we make the dump (malformed rows are excluded) and we replace the ROLLBACK with a COMMIT so that the entire dump script will be committed in stead of rolled back.

This method saved my life a couple of 100 times already \o/

To repair a corrupt database you can use the sqlite3 commandline utility. Type in the following commands in a shell after setting the environment variables:

cd $DATABASE_LOCATION
echo '.dump'|sqlite3 $DB_NAME|sqlite3 repaired_$DB_NAME
mv $DB_NAME corrupt_$DB_NAME
mv repaired_$DB_NAME $DB_NAME

This code helped me recover a SQLite database I use as a persistent store for Core Data and which produced the following error upon save:

Could not save: NSError 259 in Domain NSCocoaErrorDomain { NSFilePath = mydata.db NSUnderlyingException = Fatal error. The database at mydata.db is corrupted. SQLite error code:11, 'database disk image is malformed' }

A few things to consider:

• SQLite3 DB files grow roughly in multiples of the DB page size and do not shrink unless you use VACUUM. If you delete some rows, the freed space is marked internally and reused in later inserts. Therefore an insert will often not cause a change in the size of the backing DB file.

• You should not use traditional backup tools for SQLite (or any other database, for that matter), since they do not take into account the DB state information that is critical to ensure an uncorrupted database. Especially, copying the DB files in the middle of an insert transaction is a recipe for disaster...

• SQLite3 has an API specifically for backing-up or copying databases that are in use.

• And yes, it does seem that your DB files are corrupted. It could be a hardware/filesystem error. Or perhaps you copied them while they were in use? Or maybe restored a backup that was not properly taken?