The system for downloading data from BigQuery into R has been rewritten from the ground up to give considerable improvements in performance and flexibility.
The two steps, downloading and parsing, now happen in sequence, rather than interleaved. This means that you’ll now see two progress bars: one for downloading JSON from BigQuery and one for parsing that JSON into a data frame.
Downloads now occur in parallel, using up to 6 simultaneous connections by default.
The parsing code has been rewritten in C++. As well as considerably improving performance, this also adds support for nested (record/struct) and repeated (array) columns (#145). These columns will yield list-columns in the following forms:
Results are now returned as tibbles, not data frames, because the base print method does not handle list columns well.
I can now download the first million rows of publicdata.samples.natality in about a minute. This data frame is about 170 MB in BigQuery and 140 MB in R; a minute to download this much data seems reasonable to me. The bottleneck for loading BigQuery data is now parsing BigQuery’s json format. I don’t see any obvious way to make this faster as I’m already using the fastest C++ json parser, RapidJson. If this is still too slow for you (i.e. you’re downloading GBs of data), see ?bq_table_download for an alternative approach.
dplyr::compute() now works (@realAkhmed, #52).
tbl() now accepts fully (or partially) qualified table names, like “publicdata.samples.shakespeare” or “samples.shakespeare”. This makes it possible to join tables across datasets (#219).
dbConnect() now defaults to standard SQL, rather than legacy SQL. Use use_legacy_sql = TRUE if you need the previous behaviour (#147).
dbConnect() now allows dataset to be omitted; this is natural when you want to use tables from multiple datasets.
dbWriteTable() and dbReadTable() now accept fully (or partially) qualified table names.
dbi_driver() is deprecated; please use bigquery() instead.
The low-level API has been completely overhauled to make it easier to use. The primary motivation was to make bigrquery development more enjoyable for me, but it should also be helpful to you when you need to go outside of the features provided by higher-level DBI and dplyr interfaces. The old API has been soft-deprecated - it will continue to work, but no further development will occur (including bug fixes). It will be formally deprecated in the next version, and then removed in the version after that.
Consistent naming scheme: All API functions now have the form bq_object_verb(), e.g. bq_table_create(), or bq_dataset_delete().
S3 classes: bq_table(), bq_dataset(), bq_job(), bq_field() and bq_fields() constructor functions create S3 objects corresponding to important BigQuery objects (#150). These are paired with as_ coercion functions and used throughout the new API.
Easier local testing: New bq_test_project() and bq_test_dataset() make it easier to run bigrquery tests locally. To run the tests yourself, you need to create a BigQuery project, and then follow the instructions in ?bq_test_project.
More efficient data transfer: The new API makes extensive use of the fields query parameter, ensuring that functions only download data that they actually use (#153).
Tighter GCS connection: New bq_table_load() loads data from a Google Cloud Storage URI, pairing with bq_table_save() which saves data to a GCS URI (#155).
The dplyr interface can work with literal SQL once more (#218).
Improved SQL translation for pmax(), pmin(), sd(), all(), and any() (#176, #179, @jarodmeng). And for paste0(), cor() and cov() (@edgararuiz).
If you have the development version of dbplyr installed, print()ing a BigQuery table will not perform an unneeded query, but will instead download directly from the table (#226).
Request error messages now contain the “reason”, which can contain useful information for debugging (#209).
bq_dataset_query() and bq_project_query() can now supply query parameters (#191).
bq_table_create() can now specify fields (#204).
bq_perform_query() no longer fails with empty results (@byapparov, #206).
dplyr support has been updated to require dplyr 0.7.0 and use dbplyr. This means that you can now more naturally work directly with DBI connections. dplyr now also uses modern BigQuery SQL which supports a broader set of translations. Along the way I’ve also fixed some SQL generation bugs (#48).
The DBI driver gets a new name: bigquery().
New insert_extract_job() make it possible to extract data and save in google storage (@realAkhmed, #119).
New insert_table() allows you to insert empty tables into a dataset.
All POST requests (inserts, updates, copies and query_exec) now take .... This allows you to add arbitrary additional data to the request body making it possible to use parts of the BigQuery API that are otherwise not exposed (#149). snake_case argument names are automatically converted to camelCase so you can stick consistently to snake case in your R code.
Full support for DATE, TIME, and DATETIME types (#128).
All bigrquery requests now have a custom user agent that specifies the versions of bigrquery and httr that are used (#151).
dbConnect() gains new use_legacy_sql, page_size, and quiet arguments that are passed onto query_exec(). These allow you to control query options at the connection level.
insert_upload_job() now sends data in newline-delimited JSON instead of csv (#97). This should be considerably faster and avoids character encoding issues (#45). POSIXlt columns are now also correctly coerced to TIMESTAMPS (#98).
insert_query_job() and query_exec() gain new arguments:
quiet = TRUE will suppress the progress bars if needed.use_legacy_sql = FALSE option allows you to opt-out of the legacy SQL system (#124, @backlin)list_tables() (#108) and list_datasets() (#141) are now paginated. By default they retrieve 50 items per page, and will iterate until they get everything.
list_tabledata() and query_exec() now give a nicer progress bar, including estimated time remaining (#100).
query_exec() should be considerably faster because profiling revealed that ~40% of the time taken by was a single line inside a function that helps parse BigQuery’s json into an R data frame. I replaced the slow R code with a faster C function.
set_oauth2.0_cred() allows user to supply their own Google OAuth application when setting credentials (#130, @jarodmeng)
wait_for() uses now reports the query total bytes billed, which is more accurate because it takes into account caching and other factors.
list_tabledata returns empty table on max_pages=0 (#184, @ras44 @byapparov)
New set_service_token() allows you to use OAuth service token instead of interactive authentication.from
^ is correctly translated to pow() (#110).
Provide full DBI compliant interface (@krlmlr).
Backend now translates iflese() to IF (@realAkhmed, #53).
Compatiable with latest httr.
Computation of the SQL data type that corresponds to a given R object is now more robust against unknown classes. (#95, @krlmlr)
A data frame with full schema information is returned for zero-row results. (#88, @krlmlr)
New exists_table(). (#91, @krlmlr)
New arguments create_disposition and write_disposition to insert_upload_job(). (#92, @krlmlr)
Renamed option bigquery.quiet to bigrquery.quiet. (#89, @krlmlr)
New format_dataset() and format_table(). (#81, @krlmlr)
New list_tabledata_iter() that allows fetching a table in chunks of varying size. (#77, #87, @krlmlr)
Add support for API keys via the BIGRQUERY_API_KEY environment variable. (#49)