How to Corrupt an SQLite Database File

I read this as a damnation of POSIX filesystem semantics. File descriptors getting reused, insane locking semantics on close, allowing you to delete an open file and providing no means to prevent it, fork causing problems, unspecified behavior of sync() (is it barrier or &quot;full&quot; sync).<p>Though: Multiple copies of SQLite linked into the same application. Weird and rare scenario, but why not keep the global list of open sqlite files in a global shared memory segment?

That one is easier as you think: 2.2.1. Multiple copies of SQLite linked into the same application<p>I used two different C# libraries to access the same database. And under the hood, they both used a different SQLite library, with different native SQLite builds (of the same version though).<p>Took me some time to figure out…

Really, the only way to prevent corruption of a SQL (or any other kind of) database is to have a server process manage all accesses to the database storage. And even then....<p>SQLite is great, but I would not use it in a multi-machine, multi-processing environment.

Doesn&#x27;t point 1.2 (backing up the file in the middle of a transaction) contradict the part above about how SQLite is resistant to power failures and simply rolls back the incomplete transaction? You&#x27;d just end up with a db outdated by 1 transaction, which is fine for a backup anyway.

Does Linux yet have a config option to randomize the file descriptor number it hands out? So many times have I been bitten by silent use after close of these FDs.

During some low-impact exploratory work on my local machine recently, I launched a Jupyter Lab notebook that connected to a SQLite db that was in a directory MS One Drive had claimed. The sync processes had nuked the db within five minutes. I was able to recreate the db easily, from csv files. Important lesson learned!

&quot;Backup or restore while a transaction is active&quot;<p>Is it possible to turn off transactions alltogether in SQLite? So they function like a MyIsam table in MySql or a Aria table in MariaDB?<p>I have crunched many billions of queries over the last years in MySql and then MariaDB. I like MariaDB because it offers tables that are way faster due to no transaction overhead.<p>I know this goes against the popular opinion to use transactional tables for everything. But depending on the task at hand, the performance gain can be very well worth turning transactions off.<p>I consider trying SQLite. But if you cannot switch off transactions, performance will probably not be up to par.

<i>&quot;Unfortunately, most consumer-grade mass storage devices lie about syncing. Disk drives will report that content is safely on persistent media as soon as it reaches the track buffer and before actually being written to oxide. This makes the disk drives seem to operate faster (which is vitally important to the manufacturer so that they can show good benchmark numbers in trade magazines).&quot;</i><p>Is this also true of SSDs?

I recently saw SQLite used (and written to) in a Docker container, with the database file on a mounted volume.<p>That made me nervous!<p>I don&#x27;t know enough about how Docker implements volumes under the hood to know how likely (or not) it is to break filesystem behavior that SQLite depends on for its transactional guarantees.<p>Perhaps someone here does?

Accidentally check it into git on a multi-developer team...

Do I understand correctly that “<i>2.2.1. Multiple copies of SQLite linked into the same application</i>” is only a problem if more than one copy accesses the same database file?

An Es Kew El or A Seakewl Lite

interesting!