Posted Jun Wed 29th pm. Posted Jul Fri 1st am. Posted Jul Tue 19th pm. Posted Jul Wed 20th pm. Posted Jul Thu 21st am. Return to Thunderbird Support. Users browsing this forum: Google [Bot] and 4 guests. HarryPotter Guest.
Has anybody an idea how to get it small again? Posted Jul Fri 1st am howdy hp, i don't have such a file in tbird - only in firefox. Posted Jul Tue 19th pm In my profile folder too, it sucks. Especially since I have this profile stored on a network drive. But SQLite does use the declared type of a column as a hint that you prefer values in that format. If it can, it inserts the integer instead. If not, it inserts the string.
This feature is called type affinity. This problem occurs when your primary key is a numeric type. Change the datatype of your primary key to TEXT and it should work. Every row must have a unique primary key. For a column with a numeric type, SQLite thinks that '0' and '0. See the previous question. Hence the values are not unique. Multiple processes can have the same database open at the same time.
But only one process can be making changes to the database at any moment in time, however. But use caution: this locking mechanism might not work correctly if the database file is kept on an NFS filesystem. This is because fcntl file locking is broken on many NFS implementations. You should avoid putting SQLite database files on NFS if multiple processes might try to access the file at the same time. On Windows, Microsoft's documentation says that locking may not work under FAT filesystems if you are not running the Share.
People who have a lot of experience with Windows tell me that file locking of network files is very buggy and is not dependable. If what they say is true, sharing an SQLite database between two or more Windows machines might cause unexpected problems.
SQLite allows multiple processes to have the database file open at once, and for multiple processes to read the database at once. When any process wants to write, it must lock the entire database file for the duration of its update. But that normally only takes a few milliseconds. Other processes just wait on the writer to finish then continue about their business. Other embedded SQL database engines typically only allow a single process to connect to the database at once.
But experience suggests that most applications need much less concurrency than their designers imagine. Threads are evil. Avoid them. SQLite is threadsafe. We make this concession since many users choose to ignore the advice given in the previous paragraph. Both the Windows and Linux precompiled binaries in the distribution are compiled this way. SQLite is threadsafe because it uses mutexes to serialize access to common data structures.
However, the work of acquiring and releasing these mutexes will slow SQLite down slightly. Hence, if you do not need SQLite to be threadsafe, you should disable the mutexes for maximum performance. See the threading mode documentation for additional information. Under Unix, you should not carry an open SQLite database across a fork system call into the child process.
If you are running the sqlite3 command-line access program you can type ". Or you can type ". Either of these commands can be followed by a LIKE pattern that will restrict the tables that are displayed. For tables, the type field will always be 'table' and the name field will be the name of the table. First, when you drop database objects such as tables , views , indexes , and triggers or delete data from tables , the database file size remains unchanged. Because SQLite just marks the deleted objects as free and reserves it for the future uses.
As a result, the size of the database file always grows in size. Second, when you insert or delete data from the tables, the indexes and tables become fragmented, especially for the database that has a high number of inserts, updates, and deletes.
Third, the insert , update and delete operations create unused data block within individual database pages. It decreases the number of rows that can be stored in a single page.
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