SQLite Developer is a powerful database manager that will manage Try it! It's free and being improved every day for your comfort work with SQLite! and many many more very usefull features! 'populate table' tool (for testing databases) No joking here (or just a bit only) - it contains the most completteįeature set of all tools available. My $sql = "select Name, Writeups from employees e, groups g wh +ere e.Level = g.Level and g.Level = 'Pope (28)' order by e.The best developer's and/or admin's GUI tool for Sqlite3 in the While ( my ($name, $writeups) = $sth->fetchrow_array ) My $sth = $dbh->prepare("select Name, Writeups from employees +e, groups g where e.Level = g.Level and g.Level = 'Pope (28)' order b +y e.Writeups desc ") $dbh = DBI->connect('dbi:SQLite:dbname=:memory:',"","",) or die "Couldn't connect to database: ". My $dbfile = File::Spec->catdir($PATH, 'Big_DB.db') If you change the output preferences to put 40_000 lines on the same page it takes 0.231 sec then. It does show the list as output (1000 per page), however since there are 40_000 lines in it, it takes extra time wenn you switch to the next page of the output. ) The query below was executed by SQLiteStudio 3.1.1 on Windows 10 (32 bit) in 0.174 - 0.180 sec. ( Update: created index on Level in both tables, without index the script below is slow. I played with this query using the list of the highly esteemed monks, inserting each line 10_000 times in the sqlite table employees and using the distinct values of the column "Level" for the table groups. Just my two cents - this is rather a question than an answer :-) If you have concurrent processes/threads accessing the same sqlite file, then this might be another possible theory.Ĭan you reproduce your issue with a copy of the sqlite database, with no other process accessing the file?īy vagabonding electron (Curate) on at 15:02 UTC Googling further i also stumbled over the following article which mentions that in certain circumstances sqlite might sleep for whole seconds instead of microseconds when trying to acquire a lock. An empty result, where there should be a result, is however many times the symptom of an unhandled exception or timeout. One thing contradicting this theory however is, that you use RaiseError => 1, and as such you should get an exception when you fail to acquire the lock. Googling i stumbled across which mentions locking in combination with sqlite_busy_timeout. the file is locked through another process, and your call times out, while trying to acquire a lock. "Perl takes several seconds may return no rows, even where there are matching candidates."įrom the behaviour this makes me think of a locking/timeout issue. Some random thought based on your description (might not apply): Seeing which line of code consumes most time, might help you in identifying the root cause, and as such fixing it. I do not have the answer for you, but if i had your problem, then i would try to identify the cause through benchmarking the code with Devel::NYTProf. Reinvent the wheel, then learn The Wheel may be one day you reinvent one of THE WHEELS. PPS have you checked for database and table fragmentation? To compact the db with VACUUM can help in such cases. PS then I suppose you need transactions and commit when you've done. Update 2: now ran it on windows 7 too and it was PDQ there as well. Update: Mea culpa: I botched the indexing (didn't commit.), and with the indexes fixed it worked all right: fast, and just as fast as postgres. (Sorry, I don't know the windows invocation.) Time sqlite3 ~/employee.db "select e.* from employees e, groups g where e.sam_account_name = g.sam_account_name and g.group_name = 'whatever' order by e.last_name, e.first_name" How fast is a SQLite commandline query? Maybe you can try something like: (Then again, I know next to nothing of SQLite it's always slow-ish in my hands so maybe I do something wrong.)įWIW, postgres runs this same query in less than a millisecond, with the same data.Ĭould sqllitestudio be caching the query, or the data? It seems likely sqllitestudio is just a wrapper, from what I read on its website. SQLite is not a particularly fast database. "select * from employees where sam_account_name = ''" takes 3 seconds. I tried to repeat this performance by making an SQLite database of those two tables + indexes, together 600 MB, employees with 18M rows, groups with just 3 rows. Re: DBD::Sqlite queries slow - and gives wrong results ![]() Also, that doesn't explain why the results are different between Perl and SQL Thanks, but I run exactly the same query against exactly the same database from SQLiteStudo, and the time goes from many seconds to milliseconds. Re^2: DBD::Sqlite queries slow - and gives wrong results All power corrupts, but we need electricity.
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