How do we optimize BigQuery performance for petabyte-scale Data Warehousing in Google Cloud?
Our data warehouse in BigQuery has grown to over 2 petabytes, and we are starting to see some queries taking much longer than expected, not to mention the rising cost of "On-Demand" slots. We are using partitioned tables based on ingestion time, but some of our join operations are still extremely slow. Should we move to "Clustered Tables" to improve query pruning? Also, at what point does it make financial sense to switch from "On-Demand" pricing to "Capacity-Based" (Committed) slots? We want to ensure our analysts can still get results in seconds without our monthly Google Cloud bill doubling.
2024-06-10 in Data Science by Anthony Davis
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All answers to this question.
At 2 petabytes, you absolutely should be using Clustered Tables alongside your partitions. Partitioning is great for "time" slices, but clustering organizes your data based on the values in specific columns (like customer_id or region), which drastically reduces the amount of data scanned during joins and filters. Regarding pricing, if your baseline slot usage is consistently above 100-200 slots, moving to Flex Slots or Annual Commitments will save you a fortune compared to the $5 per TB on-demand model. Use the "BigQuery Reservation" feature to allocate specific slot capacities to different teams so a "rogue" analyst doesn't eat up your entire budget with a single bad query.
Answered 2024-06-10 by Mary Taylor
Have you tried using "Search Indexes" in BigQuery for those specific columns that your analysts are frequently filtering by? It can speed up point-lookups significantly.
Answered 2024-06-12 by Charles Wilson
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Charles, we just implemented Search Indexes on our 'Email' and 'TransactionID' columns, and the performance gain for our support team's lookups was incredible—from 15 seconds down to under 2 seconds. The best part is that it didn't require us to rewrite any SQL; BigQuery's optimizer just picked up the index automatically. It does add a bit to the storage cost, but for the user experience improvement, it was a no-brainer for our high-concurrency workloads.
Commented 2024-06-13 by Joseph Allen
Avoid "SELECT *" at all costs! In a columnar database like BigQuery, it is the number one cause of unnecessary spend and slow performance.
Answered 2024-06-14 by Sarah Jenkins
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I agree with Sarah. We actually set up a "Query Linter" that blocks any PR containing a "SELECT *" in our production data pipelines. It's a simple rule that saves us thousands of dollars.
Commented 2024-06-15 by Anthony Davis
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