I am using GCP BigQuery to run SQL queries.
As far as I know, the cost of BigQuery is charged by Slots (Workers), I'd like to know that, can Bigquery scale to 0 workers once queries finished? Is there anything I have to pay, like storage or compute engine instance?
Thank you.
NO.
BigQuery is a serverless managed database service.
It has no dependencies, it doesn't use Compute Engine Instances, or workers.
Slots concepts are for upfront payment and has nothing to do with Workers as you described.
In Bigquery you pay
your database storage
streaming insert
query costs
No.
BigQuery converts query statements into a graph of execution by dividing into multiple stages, which are composed of more granular sets of execution steps.
BigQuery model the units of work in a such a way that many potential workers may execute in parallel and each stage communicate with one another by using a distributed shuffle architecture. In BigQuery execution plan, workers are used to convey information specifically about parallelism
Related
I'm expected to have thousands of sensors sending telemetry data at 10FPS with around 1KB of binary data per frame, using IOT Core, meaning I'll get it via PubSub. I'd like to get that data to BigQuery, and no processing is needed.
As Dataflow don't have a template capable of dealing with binary data, and working with it seems a bit cumbersome, I'd like to try to avoid it and go full serverless.
Question is, what's my best alternative?
I've thought about Cloud Run service running an express app to accept the data from PubSub, and using global variable to accumulate around 500 rows in ram, then dump it using BigQuery's insert() method (NodeJS client).
How reasonable is that? Will I gain something from accumulation, or should I just insert to bigquery every single incoming row?
Streaming Ingestion
If your requirement is to analyze high volumes of continuously arriving data with near-real-time dashboards and queries, streaming inserts would be a good choice. The quotas and limits for streaming inserts can be found here.
Since you are using the Node.js client library, use the BigQuery legacy streaming API's insert() method as you have already mentioned. The insert() method streams one row at a time irrespective of accumulation of rows.
For new projects, the BigQuery Storage Write API is recommended as it is cheaper and has an enriched feature set than the legacy API does. The BigQuery Storage Write API only supports Java, Python and Go(in preview) client libraries currently.
Batch Ingestion
If your requirement is to load large, bounded data sets that don’t have to be processed in real-time, prefer batch loading. BigQuery batch load jobs are free. You only pay for storing and querying the data but not for loading the data. Refer to quotas and limits for batch load jobs here. Some more key points on batch loading jobs have been quoted from this article.
Load performance is best effort
Since the compute used for loading data is made available from a shared pool at no cost to the user,
BigQuery does not make guarantees on performance and available
capacity of this shared pool. This is governed by the fair scheduler
allocating resources among load jobs that may be competing with loads
from other users or projects. Quotas for load jobs are in place to
minimize the impact.
Load jobs do not consume query capacity
Slots used for querying data are distinct from the slots used for ingestion. Hence, data
ingestion does not impact query performance.
ACID semantics
For data loaded through the bq load command, queries will either reflect the presence of all or none of the data .
Queries never scan partial data.
I am planning to spin up a dataflow instance on google cloud platform to run some experiments. I want to get familiar with, and experiment with using apache beam to pull data from BigQuery, run some ETL jobs (in python) and streaming jobs, and finally store the result in BigQuery.
However, I am also concerned with sending my company's GCP bill through the roof. What are the main cost considerations, or any methods to estimate what the cost will be, so I don't get an earful from my boss.
Any help would be greatly appreciated, thanks!
You can use calculator to get an estimate of price of the job.
One of the most important resource on the dataflow side is CPU per hour. To limit the cpu hours, you can set the maximum machines using option maxNumWorkers in your pipeline.
Here are more pipeline options that you can set while running your dataflow job https://cloud.google.com/dataflow/docs/guides/specifying-exec-params
For BQ, you can do a similar estimate using the calculator.
I have around 1500 jobs to be implemented using Dataflow. Those jobs will be scheduled on daily basis. We may get to use huge number of DML statements using Bigquery Client library within our jobs. Listing down my concerns regarding Bigquery quotas and limits.
Reference: https://cloud.google.com/bigquery/quotas
Please confirm that do we need to take the daily usage limits of Bigquery into consideration in any of the below mentioned scenarios.
If we implement data inserts using BigqueryIO.write()
If we use DML statements (Update/Delete) using Bigquery Client Library within the Dataflow job
Please suggest.
You absolutely do need to take BigQuery quotas and limits into consideration - even when hooking into it from Dataflow.
Dataflow is just calling the BigQuery API on your behalf. Therefore, all quotas and limits still apply as if you were calling it directly yourself.
I found a couple related questions, but no definitive answer from the Google team, for this particular question:
Is a Cloud DataFlow job, writing to BigQuery, limited to the BigQuery quota of 100K rows-per-second-per-table (i.e. BQ streaming limit)?
google dataflow write to bigquery table performance
Cloud DataFlow performance - are our times to be expected?
Edit:
The main motivation is to find a way to predict runtimes for various input sizes.
I've managed to run jobs which show > 180K rows/sec processed via the Dataflow monitoring UI. But I'm unsure if this is somehow throttled on the insert into the table, since the job runtime was slower by about 2x than a naive calculation (500mm rows / 180k rows/sec = 45 mins, which actually took almost 2 hrs)
From your message, it sounds like you are executing your pipeline in batch, not streaming, mode.
In Batch mode, jobs run on the Google Cloud Dataflow service do not use BigQuery's streaming writes. Instead, we write all the rows to be imported to files on GCS, and then invoke a BigQuery load" job. Note that this reduces your costs (load jobs are cheaper than streaming writes) and is more efficient overall (BigQuery can be faster doing a bulk load than doing per-row imports). The tradeoff is that no results are available in BigQuery until the entire job finishes successfully.
Load jobs are not limited by a certain number of rows/second, rather it is limited by the daily quotas.
In Streaming mode, Dataflow does indeed use BigQuery's streaming writes. In that case, the 100,000 rows per second limit does apply. If you exceed that limit, Dataflow will get a quota_exceeded error and will then retry the failing inserts. This behavior will help smooth out short-term spikes that temporarily exceed BigQuery's quota; if your pipeline exceeds quota for a long period of time, this fail-and-retry policy will eventually act as a form of backpressure that slows your pipeline down.
--
As for why your job took 2 hours instead of 45 minutes, your job will have multiple stages that proceed serially, and so using the throughput of the fastest stage is not an accurate way to estimate end-to-end runtime. For example, the BigQuery load job is not initiated until after Dataflow finishes writing all rows to GCS. Your rates seem reasonable, but please follow up if you suspect a performance degradation.
These may be few basic questions.
When i load data into BQ tables, where exactly data stored? (If billing is already enabled). if it is data center, what would be data center capacity? Does our data co-exist with other users data?
When we fire queries, How our queries processed? What is the default compute engine used for this?
How can we increase query processing capacity?
Thanks
CP
BigQuery datacenter capacity is practically unlimited. If you plan to upload petabytes in a very short time frame you might need to contact support first just to make sure, but for normal big loads everything should be fine.
BigQuery doesn't use compute engine, but a series of very large clusters where all queries run. That's the secret to a low cost per query, without ongoing costs per hour like other alternatives.
BigQuery increases the number of CPUs involved in your query elastically as the query needs. You don't need to manage storage nor processing capacity.