google cloud dataflow - How can I improve performance of TextIO or AvroIO when reading a very large number of files? -


textio.read() , avroio.read() (as other beam io's) default don't perform in current apache beam runners when reading filepattern expands large number of files - example, 1m files.

how can read such large number of files efficiently?

when know in advance filepattern being read textio or avroio going expand large number of files, can use recently added feature .withhintmatchesmanyfiles(), implemented on textio , avroio.

for example:

pcollection<string> lines = p.apply(textio.read()     .from("gs://some-bucket/many/files/*")     .withhintmatchesmanyfiles());

using hint causes transforms execute in way optimized reading large number of files: number of files can read in case practically unlimited, , pipeline run faster, cheaper , more reliably without hint.

however, may perform worse without hint if filepattern matches small number of files (for example, few dozen or few hundred files).

under hood, hint causes transforms execute via respectively textio.readall() or avroio.readall(), more flexible , scalable versions of read() allow reading pcollection<string> of filepatterns (where each string filepattern), same caveat: if total number of files matching filepatterns small, may perform worse simple read() filepattern specified @ pipeline construction time.


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

Add new key value to json node in java -

i have json file : { "id":1, "name":"abc", "addressdetails": { "city":"newyork" } } i wanted add 1 more key-value ("pincode" : "414141") node 'addressdetails'. i tried using : objectmapper mapper = new objectmapper(); jsonnode root = mapper.readtree(new file("d://test.json")); objectnode node = mapper.createobjectnode(); node.with("addressdetails").put("pincode", "414141"); but it's not getting added, there way can ? you can try you should modify file path objectmapper mapper = new objectmapper(); objectnode nodes = mapper.readvalue(new file("d:\\test.txt"), objectnode.class); nodes.with("addressdetails").put("pincode", "414141"); mapper.writer().writevalue(new file("d:\\test.txt"), nodes);
Read more