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// Copyright 2015 Google Inc. All Rights Reserved.
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// See the License for the specific language governing permissions and
// limitations under the License.
package bigquery
import (
gax ""
bq ""
// A Job represents an operation which has been submitted to BigQuery for processing.
type Job struct {
c *Client
projectID string
jobID string
isQuery bool
destinationTable *bq.TableReference // table to read query results from
// JobFromID creates a Job which refers to an existing BigQuery job. The job
// need not have been created by this package. For example, the job may have
// been created in the BigQuery console.
func (c *Client) JobFromID(ctx context.Context, id string) (*Job, error) {
job, err := c.service.getJob(ctx, c.projectID, id)
if err != nil {
return nil, err
job.c = c
return job, nil
func (j *Job) ID() string {
return j.jobID
// State is one of a sequence of states that a Job progresses through as it is processed.
type State int
const (
Pending State = iota
// JobStatus contains the current State of a job, and errors encountered while processing that job.
type JobStatus struct {
State State
err error
// All errors encountered during the running of the job.
// Not all Errors are fatal, so errors here do not necessarily mean that the job has completed or was unsuccessful.
Errors []*Error
// Statistics about the job.
Statistics *JobStatistics
// setJobRef initializes job's JobReference if given a non-empty jobID.
// projectID must be non-empty.
func setJobRef(job *bq.Job, jobID, projectID string) {
if jobID == "" {
// We don't check whether projectID is empty; the server will return an
// error when it encounters the resulting JobReference.
job.JobReference = &bq.JobReference{
JobId: jobID,
ProjectId: projectID,
// Done reports whether the job has completed.
// After Done returns true, the Err method will return an error if the job completed unsuccesfully.
func (s *JobStatus) Done() bool {
return s.State == Done
// Err returns the error that caused the job to complete unsuccesfully (if any).
func (s *JobStatus) Err() error {
return s.err
// Status returns the current status of the job. It fails if the Status could not be determined.
func (j *Job) Status(ctx context.Context) (*JobStatus, error) {
js, err := j.c.service.jobStatus(ctx, j.projectID, j.jobID)
if err != nil {
return nil, err
// Fill in the client field of Tables in the statistics.
if js.Statistics != nil {
if qs, ok := js.Statistics.Details.(*QueryStatistics); ok {
for _, t := range qs.ReferencedTables {
t.c = j.c
return js, nil
// Cancel requests that a job be cancelled. This method returns without waiting for
// cancellation to take effect. To check whether the job has terminated, use Job.Status.
// Cancelled jobs may still incur costs.
func (j *Job) Cancel(ctx context.Context) error {
return j.c.service.jobCancel(ctx, j.projectID, j.jobID)
// Wait blocks until the job or the context is done. It returns the final status
// of the job.
// If an error occurs while retrieving the status, Wait returns that error. But
// Wait returns nil if the status was retrieved successfully, even if
// status.Err() != nil. So callers must check both errors. See the example.
func (j *Job) Wait(ctx context.Context) (*JobStatus, error) {
if j.isQuery {
// We can avoid polling for query jobs.
if _, err := j.c.service.waitForQuery(ctx, j.projectID, j.jobID); err != nil {
return nil, err
// Note: extra RPC even if you just want to wait for the query to finish.
js, err := j.Status(ctx)
if err != nil {
return nil, err
return js, nil
// Non-query jobs must poll.
var js *JobStatus
err := internal.Retry(ctx, gax.Backoff{}, func() (stop bool, err error) {
js, err = j.Status(ctx)
if err != nil {
return true, err
if js.Done() {
return true, nil
return false, nil
if err != nil {
return nil, err
return js, nil
// Read fetches the results of a query job.
// If j is not a query job, Read returns an error.
func (j *Job) Read(ctx context.Context) (*RowIterator, error) {
if !j.isQuery {
return nil, errors.New("bigquery: cannot read from a non-query job")
var projectID string
if j.destinationTable != nil {
projectID = j.destinationTable.ProjectId
} else {
projectID = j.c.projectID
schema, err := j.c.service.waitForQuery(ctx, projectID, j.jobID)
if err != nil {
return nil, err
// The destination table should only be nil if there was a query error.
if j.destinationTable == nil {
return nil, errors.New("bigquery: query job missing destination table")
return newRowIterator(ctx, j.c.service, &readTableConf{
projectID: j.destinationTable.ProjectId,
datasetID: j.destinationTable.DatasetId,
tableID: j.destinationTable.TableId,
schema: schema,
}), nil
// JobStatistics contains statistics about a job.
type JobStatistics struct {
CreationTime time.Time
StartTime time.Time
EndTime time.Time
TotalBytesProcessed int64
Details Statistics
// Statistics is one of ExtractStatistics, LoadStatistics or QueryStatistics.
type Statistics interface {
// ExtractStatistics contains statistics about an extract job.
type ExtractStatistics struct {
// The number of files per destination URI or URI pattern specified in the
// extract configuration. These values will be in the same order as the
// URIs specified in the 'destinationUris' field.
DestinationURIFileCounts []int64
// LoadStatistics contains statistics about a load job.
type LoadStatistics struct {
// The number of bytes of source data in a load job.
InputFileBytes int64
// The number of source files in a load job.
InputFiles int64
// Size of the loaded data in bytes. Note that while a load job is in the
// running state, this value may change.
OutputBytes int64
// The number of rows imported in a load job. Note that while an import job is
// in the running state, this value may change.
OutputRows int64
// QueryStatistics contains statistics about a query job.
type QueryStatistics struct {
// Billing tier for the job.
BillingTier int64
// Whether the query result was fetched from the query cache.
CacheHit bool
// The type of query statement, if valid.
StatementType string
// Total bytes billed for the job.
TotalBytesBilled int64
// Total bytes processed for the job.
TotalBytesProcessed int64
// Describes execution plan for the query.
QueryPlan []*ExplainQueryStage
// The number of rows affected by a DML statement. Present only for DML
// statements INSERT, UPDATE or DELETE.
NumDMLAffectedRows int64
// ReferencedTables: [Output-only, Experimental] Referenced tables for
// the job. Queries that reference more than 50 tables will not have a
// complete list.
ReferencedTables []*Table
// The schema of the results. Present only for successful dry run of
// non-legacy SQL queries.
Schema Schema
// Standard SQL: list of undeclared query parameter names detected during a
// dry run validation.
UndeclaredQueryParameterNames []string
// ExplainQueryStage describes one stage of a query.
type ExplainQueryStage struct {
// Relative amount of the total time the average shard spent on CPU-bound tasks.
ComputeRatioAvg float64
// Relative amount of the total time the slowest shard spent on CPU-bound tasks.
ComputeRatioMax float64
// Unique ID for stage within plan.
ID int64
// Human-readable name for stage.
Name string
// Relative amount of the total time the average shard spent reading input.
ReadRatioAvg float64
// Relative amount of the total time the slowest shard spent reading input.
ReadRatioMax float64
// Number of records read into the stage.
RecordsRead int64
// Number of records written by the stage.
RecordsWritten int64
// Current status for the stage.
Status string
// List of operations within the stage in dependency order (approximately
// chronological).
Steps []*ExplainQueryStep
// Relative amount of the total time the average shard spent waiting to be scheduled.
WaitRatioAvg float64
// Relative amount of the total time the slowest shard spent waiting to be scheduled.
WaitRatioMax float64
// Relative amount of the total time the average shard spent on writing output.
WriteRatioAvg float64
// Relative amount of the total time the slowest shard spent on writing output.
WriteRatioMax float64
// ExplainQueryStep describes one step of a query stage.
type ExplainQueryStep struct {
// Machine-readable operation type.
Kind string
// Human-readable stage descriptions.
Substeps []string
func (*ExtractStatistics) implementsStatistics() {}
func (*LoadStatistics) implementsStatistics() {}
func (*QueryStatistics) implementsStatistics() {}