Best Practices for Scaling PostgreSQL
Start supercharging your PostgreSQL today.
Written by Juan José Gouvêa and Ana Tavares
As data continues to grow at unprecedented rates, businesses across the globe are grappling with how to manage and utilize data in more effective ways. According to a report from the International Data Corporation (IDC), the “DataSphere” size (a forecast of the amount of data that will be created on an annual basis) is projected to double by 2026.
This surge in data volume places immense pressure on storage and database systems, requiring increasing scalability. With the advent of cloud computing, database management systems have grown to impressive sizes, often storing terabytes of data or more. And this trend is not going away any time soon, especially with companies and other organizations adopting data-driven strategies and diving into analytics for decision-making.
To address the challenges of data growth, enterprises must adopt modern storage solutions capable of managing data effectively. Is PostgreSQL, a battle-tested relational database management system (RDBS) with over 30 years of development and increasingly popular among developers worldwide, up to the challenge?
At Timescale, we believe the answer is “yes,” but you need to take the right approach when it comes to scaling it.
Challenges With PostgreSQL Scaling
Scaling PostgreSQL to accommodate the rapidly increasing data volumes presents several challenges. Despite PostgreSQL's flexibility and speed, it was not initially designed with today's explosion in data scale in mind, as we argued in this post about PostgreSQL TOAST.
Let’s outline some of the primary obstacles encountered when scaling PostgreSQL databases.
Ingest limits
PostgreSQL can handle significant data ingestion rates, with capabilities to insert large datasets (e.g., ~100K rows per second). However, these rates are still bounded, and as data ingestion needs grow, this limit can become a bottleneck for applications requiring high-volume data input in real time.
Table slowdown
As the size of a single table in PostgreSQL grows, it can significantly slow down query response times. The performance difference between sorting 100K rows versus 50 million rows is substantial. This slowdown affects not just query performance but also the efficiency of database operations such as updates, deletions, and maintenance tasks.
Example of sorting performance degradation
-- Example query sorting a small table
SELECT * FROM small_table ORDER BY column ASC;
-- Example query sorting a large table
SELECT * FROM large_table ORDER BY column ASC;
In the above examples, the operation on large_table would be significantly slower due to the increased data volume, illustrating the impact of table size on performance.
Batch/caching structure
PostgreSQL's architecture is designed to be computationally efficient through batch processing and caching. However, this approach introduces limitations in the continuity of processing and updating cached data.
Materialized views and cache updates
Materialized views in PostgreSQL provide a way to cache the result of a query in a table-like form, which can improve access speed for frequently executed queries. However, the data in materialized views is not always current and requires a full refresh to update, making it less suitable for applications that require real-time data.
-- Creating a materialized view
CREATE MATERIALIZED VIEW sales_summary AS
SELECT seller_no, invoice_date, sum(invoice_amt)::numeric(13,2) as sales_amt
FROM invoice
WHERE invoice_date < CURRENT_DATE
GROUP BY seller_no, invoice_date;
-- Refreshing a materialized view
REFRESH MATERIALIZED VIEW sales_summary;
The REFRESH MATERIALIZED VIEW operation can be costly for large datasets, requiring a full re-computation of the view. This process limits processing continuity and the ability to maintain real-time data freshness.
Overall challenges
The described challenges underline the fact that while PostgreSQL is a powerful and versatile database system, scaling it to meet the demands of modern applications and data volumes requires careful planning and implementation of best practices.
Addressing these challenges involves leveraging PostgreSQL features such as partitioning and replication, as well as considering architectural changes like sharding or employing additional technologies to distribute the workload more effectively.
How to Scale PostgreSQL
Scaling PostgreSQL effectively requires a combination of strategies tailored to specific needs. Let’s go through some of these strategies:
Multi-process and batch ingest
To optimize ingest rates, consider batching data into chunks, preferably between 50K to 100K rows per insert. This approach leverages PostgreSQL's strength in handling bulk data efficiently. However, for systems dealing with time-series data, where the rate of data influx is significantly high, this method alone might not suffice. An example of an insert statement for batch processing is as follows:
INSERT INTO mytable (timestamp, metric1, metric2)
VALUES
('2022-06-01 12:00:00', 1, 1.11),
('2022-06-01 13:00:00', 2, 2.21);
Storage costs
As data grows, storage becomes a critical concern. Large tables not only consume significant storage space but also become expensive to maintain. PostgreSQL offers data compression mechanisms to alleviate this, though at the cost of access speed. Designing an efficient compression strategy is, therefore, crucial for balancing storage costs against performance needs.
Indexing
Indexes are vital for enhancing query performance in PostgreSQL. By facilitating rapid data retrieval, they can significantly speed up queries. However, creating and managing indexes demands a deep understanding of the data and access patterns, as they also increase the database's storage footprint. PostgreSQL supports multiple index types, including B-tree, Hash, GiST, SP-GiST, GIN, and BRIN, each optimized for different types of queries.
Table partitions
Partitioning large tables into smaller chunks can dramatically improve query performance, especially when queries target specific segments of data. PostgreSQL supports range, list, and hash partitioning, allowing for flexible partition strategies. An example of creating a range partition on a table by date is:
CREATE TABLE measurement (
city_id int not null,
logdate date not null,
peaktemp int,
unitsales int
) PARTITION BY RANGE (logdate);
Incremental materialized views
Materialized views can cache query results and update them incrementally with new data. This strategy is particularly effective for queries run repeatedly over the same data set. However, setting up and maintaining incremental updates can be complex.
Read replicas
Implementing read replicas can distribute the query load, thereby enhancing the database's read capacity. Read replicas are synchronized copies of the primary database, serving read queries to offload the primary database. This approach requires careful management of the synchronization process to ensure data consistency.
Introducing Timescale
For databases struggling with the scaling demands of time-series data, Timescale, which supercharges PostgreSQL for demanding workloads, offers automated scaling solutions optimized for time-series data. It simplifies many of the traditional scaling challenges, offering built-in mechanisms for efficient data storage, compression, and partitioning tailored for time-series patterns.
Scaling Time-Series Data Using PostgreSQL With Timescale
In this section, we’ll delve into Timescale's solutions to common Postgres scaling problems, including data intake, storage optimization, indexing strategies, table partitioning, continuous aggregates, and read scaling—all supported by code examples and documentation. For more information on how Timescale works, head to our Docs.
Data intake
Timescale leverages PostgreSQL's architecture to offer a high intake rate, managing to coordinate multiple ingest processes. This allows the ingest operation to be broken up into parallel processes that can handle approximately 100K insertions per second. The strategy focuses on maximizing hardware and network resources, demonstrating a command pattern like:
-- Pseudo code to demonstrate parallel ingest pattern
BEGIN;
INSERT INTO conditions (time, location, temperature) VALUES (NOW(), 'office', 70.0);
COMMIT;
This approach emphasizes the use of PostgreSQL's efficient insert mechanisms while employing TimescaleDB's capability to distribute these operations across multiple background workers.
Storage space optimization
Timescale introduces tiered storage and columnar compression to tackle storage space challenges:
Tiered storage: Implements a system where data is stored across different storage media based on access frequency. This strategy is crucial for managing cost and performance across a dataset's lifecycle.
Columnar compression: TimescaleDB's time-indexed design facilitates column-level compression, often achieving up to 10x compression ratios without significant performance degradation.
For instance, configuring compression on a hypertable can be as straightforward as:
SELECT add_compression_policy('conditions', INTERVAL '7 days');
This command enables automatic compression for data older than seven days, significantly reducing storage requirements.
Advanced indexing
Timescale automates the indexing process for time-series data, eliminating the need for extensive planning and implementation of custom indexing strategies. For example, creating a time and location-based index might look like this:
CREATE INDEX ON conditions (time DESC, location);
This index enhances query performance by leveraging the inherent time-ordered nature of time-series data alongside any additional dimensions, such as location.
Hypertable partitioning
Hypertables are a central feature of Timescale, enabling automated partitioning of time-series data into manageable chunks. This partitioning happens along two dimensions—time and an optional additional attribute, facilitating efficient data management and query optimization:
SELECT create_hypertable('conditions', 'time', 'location', chunk_time_interval => INTERVAL '1 week');
Hypertable creation automates data partitioning, improving data ingestion and query performance by maintaining smaller, more manageable data sets.
Continuous aggregates
Continuous aggregates offer a powerful way to maintain real-time, incremental views on large datasets, significantly reducing the computational load for aggregate queries:
CREATE VIEW conditions_summary WITH (timescaledb.continuous) AS
SELECT time_bucket('1 day', time), AVG(temperature)
FROM conditions
GROUP BY 1;
This feature allows for efficient query performance over aggregated data, seamlessly updating as new data arrives.
Read scaling with replicas
Timescale facilitates read scaling through the creation and management of read replicas, enabling the distribution of query loads across multiple instances. This is crucial for high-availability setups and for separating analytical workloads from transactional processing:
-- Hypothetical command to add a read replica
SELECT add_read_replica('service_id', 'replica_configuration');
This command would add a read replica to the service, enhancing read capacity and system resilience.
By re-architecting some of Postgres’ best-loved features and introducing new ones, Timescale turns Postgres into a scalable solution for time-series data management that addresses the core challenges developers face when handling large volumes of data. And the best part is that you will not be slowed down by a steep learning curve: you can still use the rich and reliable Postgres ecosystem you know and love.
Start Scaling Postgres Today
Scaling PostgreSQL in today's data-intensive environments presents unique challenges, from ingestion limits to managing large tables and ensuring efficient query performance. Although PostgreSQL equips users with tools for scaling, leveraging these capabilities effectively requires a nuanced understanding of both the database system and the specific data workloads it manages.
With its suite of solutions designed to enhance PostgreSQL's native capabilities, particularly for time-series data, Timescale simplifies the complexities of data ingestion, storage optimization, and real-time analytics, allowing you to scale your PostgreSQL system more effectively.
Explore TimescaleDB's features and benefits firsthand: Try Timescale for free, no credit card required.