ClickHouse Query Performance Archives

Avoiding Costly Mistakes: Profile Events and Query Traces in a Single ClickHouse Query

Effortlessly Profile Events and Query Traces in a Single ClickHouse Query ClickHouse’s exceptional performance in analytical workloads comes with the challenge of understanding and optimizing complex query execution patterns. When queries don’t perform as expected, […]

When ClickHouse Queries Get “Stuck”

ChistaDATA Inc.

When ClickHouse Queries Get “Stuck”: Detecting, Analyzing, and Safely Killing Problematic Sessions ClickHouse is a high-performance columnar database management system designed for online analytical processing (OLAP). While it excels at handling large-scale data analytics workloads, […]

Monitoring Merge Queues in ClickHouse

Shiv Iyer

Monitoring Merge Queues in ClickHouse: Detecting and Resolving Merge Pressure ClickHouse, renowned for its high-performance columnar storage and analytical query capabilities, relies heavily on its underlying Log-Structured Merge-Tree (LSM-Tree) architecture to achieve exceptional write throughput […]

Using system.query_thread_log for Low-Level ClickHouse Performance Insights

ChistaDATA Inc.

Using system.query_thread_log in ClickHouse for Low-Level Performance Insights Introduction to Thread-Level Query Analysis In the realm of high-performance analytical databases, ClickHouse stands out for its ability to process massive datasets at lightning speed. However, as […]

ClickHouse Complete Guide to LowCardinality

ChistaDATA Inc.

ClickHouse Complete Guide to LowCardinality: When and How to Use It Introduction ClickHouse, the high-performance columnar database management system, offers a specialized data type called LowCardinality that serves as a powerful optimization tool for specific […]

ClickHouse Storage Tiering Best Practices: Moving Data Between Hot and Cold Storage with TTL

ChistaDATA Inc.

ClickHouse Storage Tiering Best Practices: Moving Data Between Hot and Cold Storage with TTL Efficient data management is critical for modern analytical databases, especially when dealing with large volumes of time-series or event-driven data. ClickHouse, […]

Troubleshooting Disk Space in ClickHouse

ChistaDATA Inc.

Troubleshooting Disk Space Issues: Managing ClickHouse Log Tables ClickHouse is a high-performance, columnar database management system optimized for real-time analytical workloads. While its speed and scalability make it ideal for large-scale data processing, one common […]

ClickHouse Search: Manticore Full Text Search with Plain Index

Essential ClickHouse Metrics

ChistaDATA Inc.

Essential ClickHouse Metrics: What to Monitor for Optimal Performance ClickHouse, the high-performance columnar database management system, exposes over 1,000 metrics for monitoring and observability 5. With such an extensive array of available metrics, selecting the […]

ClickHouse Performance: Estimated & Actual Row Counts in Execution Plans

PREWHERE vs WHERE in ClickHouse Queries

ChistaDATA Inc.

PREWHERE vs WHERE: When and How to Optimize Your ClickHouse Queries Introduction Query performance in ClickHouse often hinges on how efficiently you filter data. While most SQL users are familiar with the WHERE clause, ClickHouse […]

Understanding ClickHouse Wait Events

ChistaDATA Inc.

Understanding ClickHouse Wait Events: A Comprehensive Troubleshooting Guide Introduction Wait events in ClickHouse reveal where query execution slows down—whether from disk bottlenecks, lock contention, CPU saturation, or network latency. Mastering these signals empowers you to […]

* Everything changes over time – Our blogs/posts and comments changes over time, That’s how it should be! Whatever we comment from ChistaDATA Inc. Teams (including Shiv Iyer) and other stakeholders or guest bloggers posted here are never permanent, These things worked for us. But, there is no guarantee they will work for you too, When using the recommendations from ChistaDATA or MinervaDB or MinervaSQL or any other online resources / Google, You must test the advice before applying them to your production systems, and always invest for a robust Database DR solution, Thank you for understanding.

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