When you build a data warehouse, the important question is how to ingest data from the source system to the data warehouse. If the table is small you can fully reload a table on a regular basis, however, if the table is large a common technique is to perform incremental table updates. This post demonstrates how you can enhance incremental pipeline performance when you ingest data into BigQuery.

Setting up a standard incremental data ingestion pipeline

We will use the below example to illustrate a common ingestion pipeline that incrementally updates a data warehouse table. Let’s say that you ingest data into BigQuery from a large and frequently updated table in the source system, and you have Staging and Reporting areas (datasets) in BigQuery.

The Reporting area in BigQuery stores the most recent, full data that has been ingested from the source system tables. Usually you create the base table as a full snapshot of the source system table. In our running example, we use BigQuery public data as the source system and create reporting.base_table as shown below. In our example each row is identified by a unique key which consists of two columns: block_hash and log_index.

  CREATE TABLE reporting.base_table  --156 GB processed
PARTITION BY TIMESTAMP_TRUNC(block_timestamp, DAY) AS
SELECT log_index, data, topics, block_timestamp, block_hash
FROM bigquery-public-data.crypto_ethereum.logs
WHERE block_timestamp BETWEEN TIMESTAMP '2020-01-01' AND TIMESTAMP '2020-11-30';

In data warehouses it is common to partition a large base table by a datetime column that has a business meaning. For example, it may be a transaction timestamp, or datetime when some business event happened, etc. The idea is that data analysts who use the data warehouse usually need to analyze only some range of dates and rarely need the full data. In our example, we partition the base table by block_timestamp which comes from the source system.

After ingesting the initial snapshot you need to capture changes that happen in the source system table and update the reporting base table accordingly. This is when the Staging area comes into the picture. The staging table will contain captured data changes that you will merge into the base table. Let’s say that in our source system on a regular basis we have a set of new rows and also some updated records. In our example we mock the staging data as follows: first, we create new data, than we mock the updated records:

  CREATE TABLE staging.load_delta AS --5 GB processed
SELECT log_index, data, topics, block_timestamp, block_hash
FROM bigquery-public-data.crypto_ethereum.logs
WHERE block_timestamp BETWEEN TIMESTAMP '2020-12-01' AND TIMESTAMP '2020-12-07';
 
INSERT INTO staging.load_delta --2 GB processed
SELECT log_index, CONCAT(data, RAND()), topics, block_timestamp, block_hash
FROM bigquery-public-data.crypto_ethereum.logs TABLESAMPLE SYSTEM (5 PERCENT)
WHERE block_timestamp BETWEEN TIMESTAMP '2020-10-01' AND TIMESTAMP '2020-11-30';

Next, the pipeline merges the staging data into the base table. It joins two tables by unique key and than updates the changed value or inserts a new row

  MERGE INTO reporting.base_table T --161 GB processed
USING staging.load_delta S
ON T.block_hash = S.block_hash
 AND T.log_index = S.log_index
WHEN MATCHED THEN UPDATE SET 
  T.data = S.data
WHEN NOT MATCHED THEN INSERT (log_index, data, topics, block_timestamp, block_hash)
VALUES (log_index, data, topics, block_timestamp, block_hash);

It is often the case that the staging table contains keys from various partitions but the number of those partitions are relatively small. It holds, for instance, because in the source system the recently added data may get changed due to some initial errors or ongoing processes but older records are rarely updated. However, when the above MERGE gets executed, BigQuery scans all partitions in the base table and processes 161 GB of data. You might add additional join condition on block_timestamp:

  MERGE INTO reporting.base_table T --161 GB processed
USING staging.load_delta S
ON T.block_hash = S.block_hash
 AND T.log_index = S.log_index
 AND T.block_timestamp = S.block_timestamp
WHEN MATCHED THEN UPDATE SET 
  T.data = S.data
WHEN NOT MATCHED THEN INSERT (log_index, data, topics, block_timestamp, block_hash)
VALUES (log_index, data, topics, block_timestamp, block_hash);

But BigQuery would still scan all partitions in the base table because condition T.block_timestamp = S.block_timestamp is a dynamic predicate and BigQuery doesn’t automatically push such predicates down from one table to another in MERGE.

Can you improve the MERGE efficiency by making it scan less data? The answer is Yes. 

As described in the MERGE documentation, pruning conditions may be located in a subquery filter, a merge_condition filter, or a search_condition filter. In this post we show how you can leverage the first two. The main idea is to turn a dynamic predicate into a static predicate.

Steps to enhance your ingestion pipeline

The initial step is to compute the range of partitions that will be updated during the MERGE and store it in a variable. As was mentioned above, in data ingestion pipelines, staging tables are usually small so the cost of the computation is relatively low.

  DECLARE src_range STRUCT<date_min TIMESTAMP, date_max TIMESTAMP> --115 MB processed
DEFAULT(SELECT STRUCT(
  MIN(block_timestamp) AS date_min,  
  MAX(block_timestamp) AS date_max) FROM staging.load_delta);

Based on your existing ETL/ELT pipeline, you can add the above code as-is to your pipeline or you can compute date_min, data_max as part of some already existing transformation step. Alternatively, date_min, data_max can be computed on the Source System side while capturing the next ingestion data batch.

After computing date_min, date_max you pass those values to the MERGE statement as static predicates. There are several ways to enhance the MERGE and prune partitions in the base table based on precomputed date_min, data_max. 

If your initial MERGE statement uses a subquery, you can incorporate a new filter into it:

  BEGIN 
DECLARE src_range STRUCT<date_min TIMESTAMP, date_max TIMESTAMP> --115 MB processed
DEFAULT(SELECT STRUCT(
  MIN(block_timestamp) AS date_min,  
  MAX(block_timestamp) AS date_max) FROM staging.load_delta);

MERGE INTO reporting.base_table T --41 GB processed
USING (
  SELECT *
  FROM staging.load_delta
  WHERE block_timestamp BETWEEN src_range.date_min AND src_range.date_max) S 
ON T.block_hash = S.block_hash
 AND T.log_index = S.log_index
 AND T.block_timestamp = S.block_timestamp
WHEN MATCHED THEN UPDATE SET 
  T.data = S.data
WHEN NOT MATCHED THEN INSERT (log_index, data, topics, block_timestamp, block_hash)
VALUES (log_index, data, topics, block_timestamp, block_hash);
END;

Note that you add the static filter to the staging table and keep T.block_timestamp = S.block_timestamp to convey to BigQuery that it can push that filter to the base table. This MERGE processes 41 GB of data in contrast to the initial 161 GB. You can see in the query plan that BigQuery pushes the partition filter from the staging table to the base table:

This type of optimization, when a pruning condition is pushed from a subquery to a large partitioned or clustered table, is not unique for MERGE. It also works for other types of queries. For instance:

  SELECT * -- 41 GB processed
FROM reporting.base_table T
INNER JOIN staging.load_delta S
ON T.block_hash = S.block_hash
 AND T.log_index = S.log_index
 AND T.block_timestamp = S.block_timestamp
WHERE S.block_timestamp BETWEEN TIMESTAMP '2020-10-05' AND TIMESTAMP '2020-12-07'

And you can check the query plan to verify that BigQuery pushed down the partition filter from one table to another.

Moreover, for SELECT statements, BigQuery can automatically infer a filter predicate on a join column and push it down from one table to another if your query meets the following criteria:

• The target table must be clustered or partitioned. 
• The result size of the other table, i.e. after applying all filters, must qualify for broadcast join. Namly, the result set must be relatively small, less than ~100MB.

In our running example, reporting.base_table is partitioned by block_timestamp. If you define a selective filter on staging.load_delta and join two tables, you can see an inferred filter on the join key pushed to the target table

  SELECT * 
FROM reporting.base_table T
INNER JOIN staging.load_delta S
ON T.block_timestamp = S.block_timestamp
WHERE S.block_hash = '0x0c1caa16b34d94843aabfebc0d5a961db358135988f7498a6fdc450ad55f0870'

There is no requirement to join tables by partitioning or clustering key to kick off this type of optimization. However, in this case the pruning effect on the target table would be less significant.

But let us get back to the pipeline optimizations. Another way to enhance MERGE is to modify the merge_condition filter by adding static predicate on the base table:

  BEGIN 
DECLARE src_range STRUCT<date_min TIMESTAMP, date_max TIMESTAMP> --115 MB processed
DEFAULT(SELECT STRUCT(
  MIN(block_timestamp) AS date_min,  
  MAX(block_timestamp) AS date_max) FROM staging.load_delta);

MERGE INTO reporting.base_table T --41 GB processed
USING staging.load_delta S
ON T.block_hash = S.block_hash
 AND T.log_index = S.log_index
 AND T.block_timestamp BETWEEN src_range.date_min AND src_range.date_max
WHEN MATCHED THEN UPDATE SET 
  T.data = S.data
WHEN NOT MATCHED THEN INSERT (log_index, data, topics, block_timestamp, block_hash)
VALUES (log_index, data, topics, block_timestamp, block_hash);
END;

To summarize, here are the steps that you can perform to enhance incremental ingestion pipelines in BigQuery. First you compute the range of updated partitions based on the small staging table. Next, you tweak the MERGE statement a bit to let BigQuery know to prune data in the base table.

All the enhanced MERGE statements scanned 41 GB of data, and setting up the src_range variable took 115 MB.  Compare it with the initial 161 GB scan. Moreover, given that computing src_range may be incorporated into some existing transformation in your ETL/ELT, it results in a good performance improvement which you can leverage in your pipelines. 

In this post we described how to enhance data ingestion pipelines by turning dynamic filter predicates into static predicates and letting BiQuery prune data for us. You can find more tips on BigQuery DML tuning here.

Special thanks to Daniel De Leo, who helped with examples and provided valuable feedback on this content.

When you think about climate change, you might not consider a daily commute to work or a drive around town as big contributing factors. And yet, transport is the fastest growing source of CO2 emissions from fossil fuel, which in turn is the largest contributor to climate change. This is the key insight behind the mission of Spanish carbon-neutral multinational Acciona. The group, which provides sustainable solutions for infrastructure and renewable energy projects across 65 countries, launched an electric scooter sharing service called Acciona Mobility in 2018.

Aiming to contribute to the decarbonization of the transport sector while helping relieve traffic congestion within cities, Acciona Mobility enables users to rent electric scooters powered 100% by energy from renewable sources. Users can find, reserve, and rent the scooters at the tap of their mobile screens via the Acciona Mobility application and pay on the basis of minutes spent riding. The app, which is available free to download online, is also the gateway through which new users can register for the service, which welcomes anyone with a valid driver’s license for motorbikes. After having their right to drive, identity, and card details validated, citizens can start enjoying the service, available 24 hours a day, every day of the year.

“We needed to deploy a reliable infrastructure for a new service before understanding exactly what its scale and demand would be. Our strategy was to adopt a serverless architecture that can grow with us to sustain our long-term vision. This kind of thinking led us directly to Google Cloud.”

—Jose Luis Rosell, CIO Services Division, Acciona

“Acciona Mobility is exciting because it stems from our vision to make people’s lives easier in a sustainable way,” says Jose Luis Rosell, CIO of Acciona’s Services Division. “40% of the pollution near cities comes from private transportation. We want to help solve that problem with zero-carbon, electric, multimodal transportation that’s also convenient for people to use.”

However, Jose Luis says that building the appropriate IT infrastructure to bring the new service to life required external support. “We needed to deploy a reliable infrastructure for a new service before understanding exactly what its scale and demand would be. Our strategy was to adopt a serverless architecture that can grow with us to sustain our long-term vision,” he explains. “This kind of thinking led us directly to Google Cloud.”

Developing the transportation platform of the future

Because Acciona was already a Google Cloud customer, Jose Luis and his team reached the decision to develop the new service on Google Cloud with ease, as he explains: “We had a very positive experience working closely with the Google Cloud team during Acciona’s first project on Google Cloud, and that collaborative mentality is very important for us. We feel Google Cloud is a trustworthy partner that is willing to take risks with us and is flexible enough to lead us through business uncertainty with the right technology,” he says. “So we were confident that its technology and people could help us bring the Acciona Mobility service from theory to reality.”

This time, Acciona partnered with cloud consultancy Altostratus as well, to consult on a selection of Google Cloud products that would help develop the application quickly by making use of managed services. Acciona’s strategy was to launch the new services first in Madrid, where the company is headquartered, and then spread the vision across more cities later, if the idea worked out well in practice. Due to the scale of the project and its data needs, BigQuery was chosen as the primary data warehouse to store all the information related to the service, such as the location of scooters and their availability status. With all its data readily available on BigQuery, Acciona is able to run specific queries that help it to gain insights such as which urban areas have the highest volume of scooters being rented. Knowing this, Acciona can reorganize availability to make sure there are always enough scooters in that specific location.

Integrating it with Pub/Sub and Dataflow, Acciona ensures that the data generated by scooters is ingested and processed in real time so that users searching for scooters nearby, using the Acciona Mobility application on their phones, can always have up-to-date information at hand. Using Google Maps Platform APIs such as the Directions API, Acciona’s mobile app translates the geographical coordinates of scooters into an easy-to-read address displayed beside a visual map. Using Cloud SQL, Acciona automates the storage capacity management of the database as the number of scooters and active users grow.

Meanwhile, Google Cloud Armor protects the service against cyber breaches and distributed denial of service attacks to keep it running uninterrupted. In addition, Google Cloud itself helps to reinforce the cyber security measures with secure-by-default managed services, such as data encryption. “The managed services mean more resilience and more uptime, because we don’t need to worry about maintenance or external threats,“ says Jose Luis of the solutions protecting all information generated by the new service, which as CIO is a topic he holds dearly. “I face cybersecurity issues more confidently as a Google Cloud partner,” he adds.

“Today, we have data coming in every 15 seconds from 10,000 electric scooters around Europe. BigQuery and Cloud SQL-managed services help us handle that data very carefully and with precision so that our users don’t experience any lags when searching for scooters or returning them.”

—Jose Luis Rosell, CIO Services Division, Acciona

Expanding an 100% sustainable transport solution throughout Spain

Within two months of the decision to deploy Acciona Mobility on Google Cloud, the service was ready for launch, filling the streets of Madrid with 500 electric scooters that run 100% on renewable energy. By 2020, the number of scooters has grown to 10,000 and the service has scaled to multiple cities in and outside of Spain, including Lisbon, Milan, and Rome. To date, more than 3.5 million intracity rides have used the Acciona Mobility app, reducing CO2 emissions by more than 1,000 tons.

“Today, we have data coming in every 15 seconds from 10,000 electric scooters around Europe. BigQuery and Cloud SQL-managed services help us handle that data very carefully and with precision so that our users don’t experience any lags when searching for scooters or returning them,” says Jose Luis of the fast-growing scale of the project.

“Google Cloud enables us to keep our services always available and to scale quickly to respond to its growing demand. Our ratings have been very positive as a result. More importantly, our vision of transportation as a cleaner, more sustainable commodity is really spreading and resonating with the public.”

—Jose Luis Rosell, CIO Services Division, Acciona

Set to continue expanding, Acciona is using Google Kubernetes Engine to make sure the Acciona Mobility application has the computing capacity it needs to continue scaling to reach new markets and serve more users. On that note, Google operations tools (formerly Stackdriver) are also being deployed to help monitor, troubleshoot, and improve the performance of the application as it scales.

“Google Cloud enables us to keep our services always available and to scale quickly to respond to its growing demand. Our ratings have been very positive as a result. More importantly, our vision of transportation as a cleaner, more sustainable commodity is really spreading and resonating with the public,” he concludes.

As data environments become more complex, companies are turning to streaming analytics solutions that analyze data as it’s ingested and deliver immediate, high-value insights into what is happening now. These insights enable decision makers to act in real time to take advantage of opportunities or respond to issues as they occur.

While understanding what is happening now has great business value, forward-thinking companies are taking things a step further, using real-time analytics integrated with artificial intelligence (AI) and business intelligence (BI) to answer the question, “what might happen in the future?” Arkansas-based Tyson Foods has embraced AI/BI analytics to enable predictive insights that unlock new opportunities and drive future growth.

Creating a digital twin for connected intelligence company wide

Before using AI/BI, Tyson’s analytics capabilities consisted of traditional BI solutions focused on KPIs and simplifying data so that humans could understand it. Tyson wanted to leverage its data to uncover ways to improve current processes and grow its business. But with BI alone, Tyson struggled to use data to run the simulations and scenarios essential to make educated decisions. To keep growing, it had to embrace the complexity of its data, building ways to analyze it and use it to inform decision making. 

Tyson’s on-premises analytics solutions limited its ability to be aggressive and make intelligent, timely, prescriptive decisions. The solution was to create a digital twin to scale optimizations within business processes, moving from local optimizations to system-wide connected optimizations. Doing so meant shifting entirely to cloud computing, with an initial focus on building the ingestion component of the digital twin platform.

Investing in a digital twin enabled Tyson to accelerate new capabilities like supply chain simulation “what-if” scenarios, prescriptive price elasticity recommendations, and improvement of customer intimacy. 

Solving the ingestion problem for faster time to insights

Before its migration to Google Cloud, analytics projects that Tyson suffered from uncertainty over how to obtain the data. This problem was prolific and caused project times to be extended for weeks or even months due to the need to write and support one-off data ingestion processes at the front end. This problem also prevented the IT team from delivering analytics solutions fast enough for the business to take full advantage of them. 

To solve this analytics problem, the team created Data Ingestion Compute Engine (DICE). DICE is a Google Cloud-hosted, open-source, cloud-native ingestion platform developed to provide configuration-based, no-ops, code-free ingestion from disparate enterprise data systems, both internal and external. It is centered on three high-level goals:

1. Accelerate the speed of delivery of IT analytics solutions
2. Enable growth of IT capabilities to produce meaningful insight
3. Reduce long-term total cost of ownership for ingestion solutions

Creating DICE ingestion platform with Google Cloud services

Teams use DICE to set up secure data ingestion jobs in minutes without having to manage complex connections or write, deploy, and support their own code. DICE enables unbound scale, highly parallel processing, DevSecOps, open source, and the implementation of Lambda Data Architecture.

A DICE job is the logical unit of work in the DICE platform, consisting of immutable and mutable configurations persisted as JSON documents stored in Firestore. The job exists as an instruction set for the DICE data engine, which is Apache Beam running Dataflow to instruct which data to pull, how to pull it, how often to pull it, how to process it, when it changes, and where to direct it.

Two of DICE’s primary layers include the metadata engine and the data engine. The metadata engine is responsible for the creation and management of DICE job configuration and orchestration. It is made up of many microservices that interact with multiple Google Cloud services, including the job configuration creation API, job build configuration helper API, and job execution scheduler API.

The data engine is responsible for the physical ingestion of data, the change detection processing of that data, and the delivery of that data to specified targets. The data engine is Java code that uses the Apache Beam unified programming model and runs in Dataflow. It is comprised of streaming, jobs, and Dataflow flex template batch jobs. Logically, the data engine is segmented across three layers: the inbound processing layer, the DICE file system layer, and the target processing layer, which takes the data from the DICE file system and moves it to targets.

Rolling DICE for thousands of ingestion jobs each day

DICE was first deployed to a production environment in November 2019, and just two years later, it has more than 3,000 data ingestion jobs from more than a hundred disparate data systems, both internal and external to Tyson Foods. Most of these jobs run multiple times a day. On a daily basis the DICE environment sees more than 25,000 Dataflow jobs running and an average of 3.25 terabytes of new data being ingested.

DICE supports ingestion from many different types of technologies, including BigQuery, SQL Server, SAP HANA, Postgres, Oracle, MySQL, Db2, various types of file systems, and FTP servers. Additionally, DICE supports target platform technologies for ingestion jobs that include multiple JDBC targets, multiple file system targets, and BigQuery and queue-based store and forward technologies. 

The platform continues to see linear growth of DICE jobs, all while keeping platform costs relatively flat. With increasing demand for the platform, Tyson’s IT team is constantly enhancing DICE to support new sources and targets.

This intelligent platform keeps adding new value and makes it simple for Tyson to take advantage of its data. This innovation is a necessity in this fast-changing world of digital business in which companies must transform a high volume of complex data into actionable insight.