Enhancement: Use sqlite3 WAL mode for hash.db

[Forza-tng]

sqlite has a WAL mode that has a much better performance for btrfs filesystems. It would be good if duperemove would change to use WAL mode. It should lead to a much less fragmented sqlite database, which I guess is the biggest benefit for duperemove.

It is already possible to use WAL-mode with duperemove by doing the following.

• Run duperemove briefely to create the hash-file.
• Open the hashfile: sqlite3 hash.db
• Set WAL-mode PRAGMA journal_mode=wal;
• close sqlite3.
• Run duperemove again.

Reference to performance impact on Btrfs: https://wiki.tnonline.net/w/Blog/SQLite_Performance_on_Btrfs

[JackSlateur]

Hello @Forza-tng WAL-mode is now used in the latest release

Thank you for your report