Congratulations. This is a big milestone. The single "sqlite3.c" source file release will certainly simplify embeddeding.
I guess the single translation unit thing is why GCC is busy working on link-time optimization (and why LLVM is faster in some cases). --- [EMAIL PROTECTED] wrote: > When you do "PRAGMA locking_mode=EXCLUSIVE", it means that > SQLite will not release its EXCLUSIVE lock after its does its > first write until you either close the connection or you > do "PRAGMA locking_mode=NORMAL". There are various optimizations > that can occur when this is the case. > > There is a plot of runtime of CVSHEAD versus version 3.3.13 > at > > http://www.sqlite.org/relspeed-20070326-ephemeral.gif > > (As the name implies, this GIF will ephemeral. Do not expect it > to be there for more than a few days.) Any value less than > 1.0 means that performance has improved. The test script is > > http://www.sqlite.org/cvstrac/fileview?f=sqlite/test/speed2.test > > The orange bars show the relative performance of CVSHEAD with > no special build options. 1.0 is the performance of version 3.3.13 > so anything less than 1.0 is an improvement. The red bars show > CVSHEAD with all the source files concatenated into a single big > file and compiled as a single translation unit. Compiling this > way allows the compiler to do additional optimizations that result > in improved performance. The blue bars are the same sqlite-as-one- > great-big-source-file optimization but with -DSQLITE_OMIT_XFER_OPT=1 > defined. > > The tests are cumulative. The database that results from one test > feeds into the next. The two "insert" tests at the top both > consists of a large number (50000) of distinct INSERT statements. > These tests are dominated by the parser and code generator and > all of our recent work has been directed toward optimizing the > backend so these tests do not show any improvement. You can see > that the new "XFER Optimizer" actually results in a slight > performance drop since for each INSERT statement, the parser has > to check to see if the XFER optimization applies. (It never > does in the first two tests.) > > The interface between the B-Tree layer and the Pager layer has > been refactored. This refactoring prevented the compiler from > doing certain function inlinings that it was able to do before, > resulting in a performance drop for the orange bar. But when > the pager and b-tree modules were combined into a single source > file, the function inlining was able to occur again and so > performance improved. > > Tests select4 through select6 are about twice as fast. We believe > this is because the pager cache is no longer flushed unless the > database is changed by another process. > > VACUUM is much faster due to the XFER optimization. Furthermore, > VACUUM with the XFER optimization greatly reduces th database > fragmentation. This is (we believe) why performance is so much > better in the later tests for the orange and red bars. Operations > on a defragmented database file go much faster. > > Changes have been made to the b-tree and pager layers that omit > certain unnecessary writes to the database file and to the rollback > journal. This reduction in disk I/O results in the 20x performance > improvements seen for tests delete1 and drop1. > > CVSHEAD passes the "quick" regression tests. But we know there > are still issues with the code. CVSHEAD is not currently > recommended for use in shipping products, but it is adequate > for development work, we believe. > > In past releases of SQLite, we have made available a ZIP archive > with preprocessed source files. In the future, we may change this > so that instead of a ZIP archive full of individual files, we > ship a single "sqlite3.c" source file which contains all of the > source file in a single translation unit. By this mode of > delivery, we hope to enable users to see the performance improvements > we are seeing in our red bars. ____________________________________________________________________________________ Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
