ClickHouse Data Modeling for Postgres Users
ClickHouse acquired PeerDB to enhance PostgreSQL data replication. The article offers data modeling tips, emphasizing the ReplacingMergeTree engine, duplicate management, ordering key selection, and the use of Nullable types.
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ClickHouse has recently acquired PeerDB, a company specializing in PostgreSQL Change Data Capture (CDC), which facilitates the replication of data from PostgreSQL to ClickHouse. This article provides data modeling tips for users transitioning from PostgreSQL to ClickHouse, highlighting the differences between the two databases. ClickHouse is optimized for analytical workloads, while PostgreSQL is designed for transactional operations. The ReplacingMergeTree table engine is recommended for managing data ingestion and modifications, allowing for efficient deduplication of rows. Users can handle duplicates using the FINAL modifier in queries or the argMax function to retain the most relevant records. Additionally, ClickHouse requires explicit Nullable types for columns, and it offers a variety of data types for efficient storage. The article emphasizes the importance of selecting an appropriate ordering key for optimizing query performance, as it functions similarly to an index in PostgreSQL. Users are encouraged to define their primary key and ordering key thoughtfully to enhance performance. Lastly, the article discusses strategies for managing deleted rows and the use of materialized views to create new tables with desired ordering keys. This guide serves as an introduction to data modeling in ClickHouse for PostgreSQL users, with plans for further exploration of advanced topics in future installments.
- ClickHouse acquired PeerDB to simplify data replication from PostgreSQL.
- The ReplacingMergeTree engine is essential for efficient data ingestion and deduplication.
- Users can manage duplicates using the FINAL modifier or argMax function in queries.
- Choosing the right ordering key is crucial for optimizing query performance.
- ClickHouse requires explicit Nullable types for columns, differing from PostgreSQL's handling of NULL values.
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5 commentsI'm wondering if the situation is different with clickhouse? Or if it is just that no one cares as your requests to clickhouse are supposed to be less frequent and so it is not a problem if the request takes several minutes to complete?
With a materialized view like that, a simple "final" for deduplication won't work anymore, right? And the other two deduplication methods will probably cause performance problems on large-ish tables.
Related
ClickHouse acquires PeerDB to expand its Postgres support
ClickHouse has acquired PeerDB to enhance Postgres support, improving speed and capabilities for enterprise customers. PeerDB's team will expand change data capture, while existing services remain available until July 2025.
Does PostgreSQL respond to the challenge of analytical queries?
PostgreSQL has advanced in handling analytical queries with foreign data wrappers and partitioning, improving efficiency through optimizer enhancements, while facing challenges in pruning and statistical data. Ongoing community discussions aim for further improvements.
Change Data Capture (CDC) Tools should be database specialized not generalized
PeerDB focuses on Postgres for Change Data Capture, minimizing pipeline failures and load impacts. Their customers manage data sizes from 300GB to 20TB, necessitating ongoing improvements as Postgres evolves.
Show HN: Storing and Analyzing 160 billion Quotes in ClickHouse
ClickHouse is effective for managing large financial datasets, offering fast query execution, efficient compression, and features like data deduplication and date partitioning, while alternatives like KDB and Shakti are also considered.
Beyond logical replication: pg_easy_replicate Supports Tracking DDL Changes
pg_easy_replicate now supports tracking schema changes in PostgreSQL, allowing replication of DDL changes like adding columns. It enhances flexibility and ensures schema synchronization during database migrations and upgrades.