BigQuery Tip: Use SEARCH Indexes for Efficient Data Retrieval

Search indexes in BigQuery are used for retrieving data more efficiently from unstructured or semi-structured data. They are particularly useful when you have a big table (>10 GB) with STRING or JSON columns on which you perform text analysis. Search indexes can optimize the usage of SEARCH function as well as other string operators like STARTS_WITH, IN, =, or LIKE.

To create a search index in BigQuery, you can use the following SQL statement:

CREATE SEARCH INDEX term_search_index ON dataset.table_name(ALL COLUMNS/1 or more columns);

You can choose to index all columns or just a specific subset of columns that are of interest and have compatible datatypes.

To check if a search index is being used in BigQuery, you should look at the 'Job Information' section of your query execution. This section will indicate whether an index was used and, if not, it will provide the reason why it wasn't utilized.

Words of caution when using search indexes in BigQuery include:

• They work best when there are a lot of distinct values in the data, which means high query selectivity.
• If you've indexed all the columns, any new compatible (STRING, JSON) column added to that table will also be indexed automatically.