java - How to import a CSV file into a BigQuery table without any column names or schema? -


i'm writing java utility import few csv files gcs bigquery. can achieve bq load, wanted using dataflow job. i'm using dataflow's pipeline , pardo transformer (returns tablerow apply on bigqueryio) , have created stringtorowconverter() transformation. here actual problem starts - forced specify schema destination table although don't want create new table if doesn't exist - trying load data. not want manually set column name tablerow have 600 columns. 

public class stringtorowconverter extends dofn<string, tablerow> {  private static logger logger = loggerfactory.getlogger(stringtorowconverter.class);  public void processelement(processcontext c) {     tablerow row = new tablerow();               row.set("do not know column name", c.element());     c.output(row); } }

moreover, assumed table exists in bigquery dataset , don't need create it, , csv file contains columns in correct order.

if there's no workaround scenario , column name needed data load, can have in first row of csv file.

any appreciated.

to avoid creation of table, should use bigqueryio.write.createdisposition.create_never of bigqueryio.write during pipeline configuration. source: https://cloud.google.com/dataflow/java-sdk/javadoc/com/google/cloud/dataflow/sdk/io/bigqueryio.write

you don't need know bigquery table schema upfront, can discover dynamically. instance, can use bigquery api (https://cloud.google.com/bigquery/docs/reference/rest/v2/tables/get) query table schema , pass parameter class stringtorowconverter. option , assuming first row header, skip first row , use map rest of file correctly.

the code below implements 2nd approach , configures output append existing bigquery table.

public class dfjob {      public static class stringtorowconverter extends dofn<string, tablerow> {          private string[] columnnames;          private boolean isfirstrow = true;          public void processelement(processcontext c) {             tablerow row = new tablerow();              string[] parts = c.element().split(",");              if (isfirstrow) {                 columnnames = arrays.copyof(parts, parts.length);                 isfirstrow = false;             } else {                 (int = 0; < parts.length; i++) {                     row.set(columnnames[i], parts[i]);                 }                 c.output(row);             }         }     }      public static void main(string[] args) {         dataflowpipelineoptions options = pipelineoptionsfactory.create()                 .as(dataflowpipelineoptions.class);         options.setrunner(blockingdataflowpipelinerunner.class);          pipeline p = pipeline.create(options);          p.apply(textio.read.from("gs://dataflow-samples/myfile.csv"))                 .apply(pardo.of(new stringtorowconverter()))                 .apply(bigqueryio.write.to("mytable")                         .withcreatedisposition(bigqueryio.write.createdisposition.create_never)                         .withwritedisposition(bigqueryio.write.writedisposition.write_append));          pipelineresult result = p.run();     } }

Comments

Post a Comment

Popular posts from this blog

Is there a better way to structure post methods in Class Based Views -

i'm using class based views in django , never specify url in ajax calls , omit action parameter in form because know these requests go through post method of class based view. notice view - profile page make many requests depending on user updating on page - post method become convoluted , if/else mess example: def post(self, request, *args, **kwargs): # handle user changing available date if request.post.get('availabledate') != none: self.updateavailabledate(request) return jsonresponse({'result':'success'}) if request.post.get('newprojectname') != none: creative_user = creativeuserprofile.objects.get(id = request.user.id) project = project.create_project(creative_user, request.post['newprojectname']) project.save() return jsonresponse({'projectid': project.id }) if request.post.get('projectimage') != none , request.files['file']: proj
Read more

performance - Why is XCHG reg, reg a 3 micro-op instruction on modern Intel architectures? -

i'm doing micro-optimization on performance critical part of code , came across sequence of instructions (in at&t syntax): add %rax, %rbx mov %rdx, %rax mov %rbx, %rdx i thought had use case xchg allow me shave instruction , write: add %rbx, %rax xchg %rax, %rdx however, dimay found agner fog's instruction tables , xchg 3 micro-op instruction 2 cycle latency on sandy bridge, ivy bridge, broadwell, haswell , skylake. 3 whole micro-ops , 2 cycles of latency! 3 micro-ops throws off 4-1-1-1 cadence , 2 cycle latency makes worse original in best case since last 2 instructions in original might execute in parallel. now... cpu might breaking instruction micro-ops equivalent to: mov %rax, %tmp mov %rdx, %rax mov %tmp, %rdx where tmp anonymous internal register , suppose last 2 micro-ops run in parallel latency 2 cycles. given register renaming occurs on these micro-architectures, though, doesn't make sense me done way. why wouldn't register renamer
Read more

jquery - Responsive Navbar with Sub Navbar -

good day, forgive me nav vocabulary not best. if question confusing apologize. i'm working on navigation bar needs centered on page @ 768px , above. items in nav open (or perhaps toggle) subnav lives directly below. these nav should appear centered on page. i have been able work through responsive portion of nav bar, having main items align vertically , sub nav menu of each item roll out below, , gave them indent separation. working well. however, issue not responsive side, behavior @ width greater 768px. happens toggling menu's sub navigation pushes other main items down page below sub nav. here's code: $(document).ready(function () { //stick in fixed 100% height behind navbar don't wrap $('#slide-nav.navbar-inverse').after($('<div class="inverse" id="navbar-height-col"></div>')); $('#slide-nav.navbar-default').after($('<div id="navbar-height-col"></d
Read more