SQLite – What are .acd, .ard and related file types

For me your last line contradicts the subject (blob vs text), so probably I mistook your idea. But what about making your log file an INSERT statement on the fly? Then feed that into your desired sqlite database. I mean something like this:

$ cat test.sql
INSERT INTO test
SELECT 'something
anything';

$ sqlite3 test < test.sql

$ sqlite3 test
SQLite version 3.6.22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> SELECT * FROM test;
something
anything
sqlite>

The WAL file records all changes to the database since the last checkpoint.

(Automatic) checkpoints cannot run when the database is locked, so ensure that there is no other connection with an active transaction.

The documentation says:

By default, the auxiliary write ahead log and shared memory files used for transaction control are automatically deleted when the latest connection to the database closes.

So ensure that all database connections are closed at some time.

(If you have disabled deleting WAL files with SQLITE_FCNTL_PERSIST_WAL, you have to set PRAGMA journal_size_limit to a nonnegative value to truncate the WAL file to zero bytes in that situation.)