mysql - Python Pandas - Using to_sql to write large data frames in chunks -


i'm using pandas' to_sql function write mysql, timing out due large frame size (1m rows, 20 columns).

http://pandas.pydata.org/pandas-docs/stable/generated/pandas.dataframe.to_sql.html

is there more official way chunk through data , write rows in blocks? i've written own code, seems work. i'd prefer official solution though. thanks!

def write_to_db(engine, frame, table_name, chunk_size):      start_index = 0     end_index = chunk_size if chunk_size < len(frame) else len(frame)      frame = frame.where(pd.notnull(frame), none)     if_exists_param = 'replace'      while start_index != end_index:         print "writing rows %s through %s" % (start_index, end_index)         frame.iloc[start_index:end_index, :].to_sql(con=engine, name=table_name, if_exists=if_exists_param)         if_exists_param = 'append'          start_index = min(start_index + chunk_size, len(frame))         end_index = min(end_index + chunk_size, len(frame))  engine = sqlalchemy.create_engine('mysql://...') #database details omited write_to_db(engine, frame, 'retail_pendingcustomers', 20000)

update: functionality has been merged in pandas master , released in 0.15 (probably end of september), @artemyk! see https://github.com/pydata/pandas/pull/8062

so starting 0.15, can specify chunksize argument , e.g. do:

df.to_sql('table', engine, chunksize=20000)

Comments

Post a Comment

Popular posts from this blog

php - Vagrant up error - Uncaught Reflection Exception: Class DOMDocument does not exist -

i've set bento/ubuntu-16.04 vagrant box using php 5.6, , getting following error quite few times when try , run shell script: "uncaught reflection exception: class domdocument not exist". i've tried adding following top of script (not together), each no success: "sudo apt-get install php5.6-xml", "sudo apt-get install php5-xml", "sudo apt-get install php-dom" i've tried resetting server "sudo service apache2 restart". does have suggestions?
Read more

vue.js - Create hooks for automated testing -

Image
qa guys complained can't automate frontend testing. because our html looks same outside. lazy hack did this <template> <div :role="$options.name"> ... </div> </template> <script> export default { name: 'vmcomponentname' } </script> which takes name script , applies html. in browser get: <div role="vmcomponentname"> ... </div> line :role="$options.name" goes in every component. is there dry er solutions? please share. additional details i'll explain in details looking for. imagine have vmusercreate form creates user. test case can create user . to automatically test without role, have use following selector: .wrapper > .wrapper > .wrapper > .submit-button the test extremely brittle (will break lot). if use roles can use [role="vmusercreateform"] .submit-button selector. many folds less brittle. so basically, i'm
Read more

.htaccess - ERR_TOO_MANY_REDIRECTS htaccess -

could can explain me .htaccess code doing? rewriterule ([0-9]+)/([^t]{1}[a-za-z0-9_-]{0,})\.([^s]{1}[a-za-z0-9]+)$ ../items/go.php?u=$1/$2.$3 i have folder : mywebsite.com/download/folder1/ .htaccess file in uplevel mywebsite.com/download/ folder contains code above. when access file directly path mywebsite.com/download/folder1/file.mp4 returns error : mywebsite.com redirected many times. try clearing cookies. err_too_many_redirects i tried clear browser cookies issue persist. issue solved when commented out htaccess line above. this rule appears looking specific pattern consisting of: <numbers>/<alphanumeric string not starting t , other conditions applied>.<alphanumeric string not starting s> then redirecting user's browser go.php parsed filename passed file arguments. err_too_many_redirects due infinite redirect loop. without knowing other rewriterule statements present difficult narrow down exact cause. can narrow down
Read more