Database Reference
In-Depth Information
Set maxResults on Your Queries
If you set the
maxResults
flag on a query to a value that isn't too large
(say, 1000 results), you reduce the chances of hitting a connection
error. Large HTTP responses can fail in many different places and
many different ways; if you request smaller results you can always go
back and fetch more. Most of the time, you actually are only interested
in the first few results; requesting more is just going to take longer to
download.
It is easy to confuse the
maxResults
field with the
LIMIT
keyword in
the query. The
LIMIT
keyword controls how many results are
computed by the query engine and stored in the result table. The
maxResults
field controls only how many results are returned in the
first page of results. Your query might return many more rows, which
would be stored in the query result temporary table in BigQuery. For
example, if your query returned a million rows and you set
maxResults
to 10,
Jobs.query()
would return only the first 10 rows.
You can page through the rest, however, by calling
Jobs.getQueryResults()
.
There is also an API design-related reason that
Jobs.query()
is a
POST
operation instead of a
GET
. HTTP
GET
requests are not supposed to make
any state changes. They can be crawled, pre-fetched, cached, are susceptible
to double-dispatch, and so on. However, running a query can cost you
money. It would not seem right to have an HTTP
GET
run up a bill, so the
Jobs.query()
method is exposed as a
POST
operation, not a
GET
.
