Why does DBD::SQLite have a different query plan for an SQL statement -


i have insert ... select ... from sql statement runs acceptably fast when executed sqlite's command line shell.

however, if execute same statement (copy/pasted) perl's dbi::sqlite, statement becomes slow.

the reason must execution plan: when let statemtent explained shell , within dbi::sqlite, they're different: fast version uses optimal indexes , table order, slow version chooses access tables in less optimal way.

so, have 2 questions. why plan different? not have expected that. , how can make plan used in perl environment same in shell?


Comments

Post a Comment

Popular posts from this blog

resizing Telegram inline keyboard -

telegram's inline keyboard great feature lots of different use cases. inline buttons added list of items this: inline_keyboard = [[inlinekeyboardbutton(text="button", callback_data="button"), inlinekeyboardbutton(text="reset",callback_data="reset")]] inline_keyboard_markup = inlinekeyboardmarkup(inline_keyboard) update.message.reply_text("hi", reply_markup=inline_keyboard_markup) the above code adds 2 buttons each half width of chat screen. i know the normal keyboard button there resize_keyboard parameter somehow can used. my question is there way resize inline buttons ? example make full width or quarter width. unfortunately, can't now. :( you can suggest @botsupport , might add feature next version.
Read more

command line - How can a Python program background itself? -

consider following python command-line program. doesn't work because incomplete, think illustrates problem: #!/usr/bin/python3 import multiprocessing pool = multiprocessing.pool() task in expensive_iterator_with_user_interaction(): pool.call_async(expensive_computation, (task,)) pool.close() print("dear user, may press ctrl-z , bg script.") pool.join() thus, problem scripts needs user input while it's launching expensive parallel processes. there moment when user interaction not needed anymore. then, ask user background process shell actions. however, can achieved program itself? (side note: core of problem entanglement of user input firing “expensive computations”. therefore, cannot separate both in 2 scripts, , letting 1 spawning other daemon.) the command screen may you. use screen -l create new session , run application. after inputting data, can press " ctrl-a " , press " d " on keyboard detach session. now
Read more

php - "cURL error 28: Resolving timed out" on Wordpress on Azure App Service on Linux -

Image
my wordpress installation on azure app service on linux using custom docker container has slow response times. pages take around 20-40 seconds load. i have troubleshooting plugin installed indicates problem "curl error 28: resolving timed out after n milliseconds" when making requests following urls https://api.wordpress.org/core/version-check/1.7/ http://api.wordpress.org/core/version-check/1.7/ https://api.wordpress.org/plugins/update-check/1.1/ http://api.wordpress.org/plugins/update-check/1.1/ https://api.wordpress.org/themes/update-check/1.1/ http://api.wordpress.org/themes/update-check/1.1/ curl works fine on scm-site command line. example works ok. curl -x post http://api.wordpress.org/core/version-check/1.7/ edit if ssh container , run php code, works fine. <?php $url = 'http://api.wordpress.org/core/version-check/1.7/'; $fields = array( 'version' => urlencode('4.8.1'), 'php' => urlencode(
Read more