Golang sqlite portable#
Golang sqlite code#

The actual size of an implementation is of course heavily dependent on the programming environment as well. I wonвЂ™t be giving actual implementations here, so the sizes will be rough estimates for comparison purposes.

Golang sqlite code#

Implementation size Obviously, a solution that requires only a few lines of code to implement is preferable over one that requires several levels of abstraction in order to be usable. CriteriaД«efore looking at some available solutions, letвЂ™s first determine the criteria we can use to evaluate them. This feature may prove useful to optimize certain situations, but does not open up new possibilities of communicating with a shared database. The semantics of this feature have changed with different SQLite versions and appear to have stabilised in 3.5.0. When using multiple database connections within a single process, SQLite offers a facility to allow sharing of its cache, in order to reduce memory usage and disk I/O. I also believe that the previously mentioned restriction on having to finalize statements has been relaxed in this version, so keeping prepared statements in memory and passing them among different threads becomes possible. The error fetching functions and sqlite3_last_insert_row_id(), among others, are still useless without explicit locking in the application. I canвЂ™t recommend making use of this facility, however, as there are still many issues with the API. SQLite will internally manage locks to avoid any data corruption.

Since SQLite 3.5.0, released in 2007, a single SQLite connection can be used from multiple threads simultaneously. In practice this means that it is not possible to keep a prepared statement in memory for later executions. But even with 3.3.1 and later there is an annoying restriction: A connection can only be passed to another thread when any outstanding statements are closed and finalized. Doing this with older versions is not advisable, as explained in the SQLite FAQ. Since SQLite 3.3.1, which was released in early 2006, it is possible to move a single database connection along multiple threads. This doesnвЂ™t mean all that much, unfortunately: The only thing thread safe means in this context is that you can use SQLite3 in multiple threads, but a single database connection should still stay within a single thread. It should be fairly safe to assume that SQLite binaries provided by most systems, if not all, are compiled with thread safety enabled.

Golang sqlite portable#

Nonetheless, it is wise to remain portable with different SQLite versions, especially when writing programs that dynamically link with some random version installed on someoneвЂ™s system. The advices are therefore a little on the conservative side. Someone has tried to organize this before on a single page, and while this indeed gives a nice overview, it has unfortunately not been updated since 2006. The official documentation mentions threading support several times in various places, but this information is scattered around and no good overview is given. LetвЂ™s first see what SQLite3 itself has to offer in terms of threading support. Which brought me to the following questions: What solutions are available for providing multi-threaded access to an SQLite database? What problems may I run in to? I was unable to find a good overview in this area on the net, so I wrote this article with the hope to improve that situation. Overall responsiveness of the program would significantly improve when the threads could access the database without involvement of the main thread. The main thread is also responsible for keeping the user interface responsive and handling most of the network interaction. Serializing all database access through the main thread wouldnвЂ™t have been very hard to implement in this particular case, but that would have been far from optimal. ItвЂ™s called sqlasync and is part of my Ylib library collection.) IntroductionДЄs I was porting ncdc over to use SQLite3 as storage backend, I stumbled on a problem: The program uses a few threads for background jobs, and it would be nice to give these threads access to the database. (Minor update: I abstracted my message passing solution from ncdc and implemented it in a POSIX C library for general use. 7446 0D32 B808 10EB A9AF A2E9 6239 4C69 8C27 39FA Multi-threaded Access to an SQLite3 Database