A process crashed while trying to commit an insert of 2-3 million rows. Now, I'm finding the database file is locked for all activity, including reading, dumping, and running an integrity check.
Can I unlock this database in some way or get sqlite3 to recover the file?
Is there any way of recovering the contents of this database file? I do have a backup from 24 hours ago, but a variety of other data will be lost if I have to do a complete rollback to an older version of the database.
Code below:
$ sqlite3 dbFile.sqlite
SQLite version 3.19.3 2017-06-08 14:26:16
Enter ".help" for usage hints.
sqlite> PRAGMA integrity_check;
Error: database is locked
sqlite> .tables
Error: database is locked
sqlite> SELECT * FROM dbTable LIMIT 1;
Error: database is locked
Running fuser on the database file indicates that no processes are currently attempting to access the file. There is a hot file in the same directory (i.e. dbFile.sqlite-journal exists).
Using stat, I see that the folder in question is of type panfs, which seems likely to be the cause of the issue. What can I do here?
Notably not a duplicate of this question, as the database is (1) not locked by any running process, as mentioned above, (2) locked for reading as well, and (3) due to the full read/write lock the .dump solution in this answer is inapplicable (as .dump fails).
Closest related question is this question, although that one is on a different NFS filesystem.
Apparently, the PanFS server(s) did not notice the crash, and so still report the write lock.
You could try to unmount and re-mount the file system on this machine, if possible.
Alternatively, copy both files (database and journal) elsewhere. When you open that database, SQLite will roll back the partial transaction.
Related
I have a huge problem... I am developing desktop app with SQLite but during copy/paste process I lost a power and process was terminated so base was lost. However, I found a way to recover it but base is encrypted. When I try to open connection using conn.Open(); I get this error. If I try to open it with DB Browser for SQLite it asks me a SQLCipher encryption password so it seams to me that data is lost..
Is there any default password ?
Why did this happen and how to prevent it from happening again ?
What can I do ?
Thanks in advance.
Also check that SQLite version you're "connecting" with aligns with the DB file version.
For example, here's a DB file written by SQLite version 3+:
$ file foobar.db
foobar.db: SQLite 3.x database, last written using SQLite version 3027002
And here I also have 2 versions of sqlite:
$ sqlite -version
2.8.17
$ sqlite3 -version
3.27.2 2019-02-25 16:06:06 bd49a8271d650fa89e446b42e513b595a717b9212c91dd384aab871fc1d0alt1
Obviously in hindsight, opening foobar.db with sqlite version 2 will fail, yielding the same error message:
$ sqlite foobar.db
Unable to open database "foobar.db": file is encrypted or is not a database
But all is good with the correct version:
$ sqlite3 foobar.db
SQLite version 3.27.2 2019-02-25 16:06:06
Enter ".help" for usage hints.
sqlite>
sqlite> .databases
main: /tmp/foobar.db
sqlite>
The error message is a catch-all, simply meaning that the file format was not recognized.
Ok, finally found a solution that works so posting the answer if anybody will have same trouble as I did..
First of all, use good recover software. For repairing the database I found 3 solutions that work without backup :
Open corrupted database using DB Browser an Export Database to SQL. Name it however you want. Then, create new database and import database from SQL.
There is software that repairs corrupted databases. Download one and use it to repair the database.
Download "sqlite3" from sqlite.org and in command line navigate to folder where "sqlite3" is unzipped. Then try to dump the entire database with .dump, and use those commands to create a new database:
sqlite3 corrupt_table_name.sqlite ".dump" | sqlite3 new.sqlite
I had the same error when I was trying to access a db dump in another system compared to compared to where it was obtained. When I tried to open on a dev machine, it threw the reported error in this thread:
$ sqlite3 db_dump.sqlite .tables
Error: file is encrypted or is not a database
This turned out to be due to the differences in the sqlite version between those systems. This dev system version was 3.6.20.
The version on the production system was 3.8.9. Once I had the sqlite3 upgraded to same version, I was able to access all its data. I am just showing below the tables are displayed as expected:
# sqlite3 -version
3.8.9
# sqlite3 db_dump.sqlite .tables
capture diskio transport
consumer filters processes
This error is rather misleading to begin with, though.
If you've interacted with the database at some point while specifying journal_mode = WAL, and then later try to use the database from a client that does not support WAL (< v3.7.0), this error can also come up.
As noted in the SQLite documentation under Backwards Compatibility, to resolve that without having to recreate the database, explicitly set the journal mode to DELETE:
PRAGMA journal_mode=DELETE;
Your database did not become encrypted (this is only one of the two options in the error message).
Your data recovery tool did not recover the correct data; what you have in the file is something else.
You have to restore the database file from the backup.
The issue is with sqlcipher version upgrade in my case, Whenever I update my pod it automatically upgrade the sqlcipher and the error occurred.
For a quick fix just manually add the SDK instead of Pod install. And for a proper solution use this link GitHub Solution
I'm finding that new sqlite3 database files are locked before any use that I am aware of.
sqlite3 new.sqlite
sqlite> SELECT * FROM SQLITE_MASTER;
Error: database is locked
lsof on the new file is empty. Copying the database file to a new location doesn't help. Permissions on the file are OK.
How else can I determine why a new sqlite3 file might be locked?
Looking at the docs, my best guess is that this is occuring because the database file is on an NFS mount for Vagrant. According to the docs:
One should note that POSIX advisory locking is known to be buggy or
even unimplemented on many NFS implementations ... Your best defense
is to not use SQLite for files on a network filesystem.
https://www.sqlite.org/lockingv3.html
I was able to resolve the issue by setting file permissions on the mounted folder on the host machine.
I've recovered data from a formatted hard drive for use in a lawsuit. The data is Skype logs, which are stored in SQLite3 databases. Unfortunately, the disk was formatted and a new copy of OS X was installed on the drive. I scanned the drive and found the files I am looking for, but it seems that the database I'm after is corrupt.
I tried the following command I found by searching on SO:
$ sqlite3 mydata.db ".dump" | sqlite3 new.db
Unfortunately, dumping this way excludes the table of records I'm looking for (Messages). Since I can get the format of the DB from Skype by just logging in with another account and generating a new main.db for it, do I have any additional options for extracting the contents of the corrupt DB? Failing that, is there a way to export the raw contents of the database in a text file or something? I only care about grabbing certain messages, which I can search for.
When the database is corrupt, the ".dump" command extracts all of the usable information, but then ends with a ROLLBACK because it encountered corruption.
Instead, store the output in a file:
$ sqlite3 mydata.db ".dump" > mydata.dump
Then, you can view the data directly in that file, or you can change the last line from "ROLLBACK" to "COMMIT" using a text editor. After that, you can load the valid portion of the data into a database using:
$ sqlite3 new.db < mydata.dump
First check for the PRAGMA integrity_check in command console and click on play button, note down the errors and repair them seperately or try exporting and then importing SQL file to new database and restart the database, it generally removes the slug files stored in the cache. If the above method does not work out then you can try SQLite database recovery tool https://www.recoveryandmanagement.com/repair-sqlite-database-manually/
While a backup of a sqlite db is going on (via the .backup command), is the sqlite db locked to prevent writes?
This answer seems to suggest that the db is not locked.
sqlite3 shell command '.backup' and transaction
However, I could not find a definite source in the documentation.
According to the documentation a shared (read-only) lock is acquired.
http://www.sqlite.org/backup.html
I have a script that was reading data from a sqlite3 database and while this script was running I made a copy of the database cp mydatabase mydatabase.bak. Will this affect either the script that was reading from the db or the copy of the db? I had a look at the sqlite documentation here [0] but I didn't put a lock on the db as per the instructions.
[0] http://www.sqlite.org/backup.html
Copying the file should be analogous to another application reading the database, so it shouldn't be a problem. Multiple applications can safely read the database file at the same time (per the SQLite FAQ).
As another point, consider that you can read from a database even if the database and its directory both lack write permissions. Since in that scenario there's no way for the reading application to be modifying the database file or creating a temp file that needs to be incorporated into it, there's no way for any of a number of simultaneously reading applications to affect what any of the others see.