Database

Problem: The client experienced a problem with query slowness in their PostgreSQL database. Several queries were running slowly, and the application became unresponsive during the issue. The client required assistance in diagnosing and optimizing the queries contributing to the performance issues. Process: Step 1 – Initial Investigation The expert reviewed the PGAWR reports for the […]

Problem: The client encountered a high availability issue in their Cassandra cluster, consisting of five nodes deployed on AWS EC2. After shutting down two servers (10.51.44.25 and 10.51.46.144), it became impossible to connect to the database, even though the other nodes remained online. The issue manifested as an authentication error when trying to connect to […]

Problem: The client faced intermittent downtimes in their PostgreSQL cluster, which is managed by Patroni for high availability. These downtimes were particularly prominent during failover events when the system failed to transition smoothly between nodes during leader elections. As a result, PostgreSQL was unable to maintain continuity of service, affecting the application performance. Logs from […]

Problem: The client observed inconsistent behavior in Elasticsearch search results when searching for strings containing reserved characters, such as colons, slashes, parentheses, and curly braces. These inconsistencies were most notable when the query string included special characters without proper escaping or when using quotes around the search values. This caused mismatches in expected results, with […]

Problem: The customer experienced issues with their Cassandra database, specifically with write failures and slow performance during nodetool repair operations. These issues were affecting the application’s ability to interact with the database, resulting in delays and failure to write data. The Cassandra cluster, consisting of 3 nodes in each of two data centers (US East […]

Problem: The client reported an issue where Apache Cassandra nodes in their multi-datacenter cluster were logging frequent errors related to SSL certificate validation, with entries like: DEBUG [Native-Transport-Requests-1] 2025-01-23 08:54:27,794 ServerConnection.java:140 - Failed to get peer certificates for peer /10.110.151.78:36376 javax.net.ssl.SSLPeerUnverifiedException: peer not verified Despite these log entries, the cluster continued to function normally, but […]

Problem: The client reported high memory usage on a production Apache Cassandra node, accompanied by frequent errors related to the ThreadPoolExecutor shutting down. This led to instability in the Cassandra service, including errors like java.util.concurrent.RejectedExecutionException, and resulted in a failure to execute repairs. Process: Step 1: Initial Identification The error logs provided by the client […]

Problem: The client needed to upgrade their production Apache Cassandra system from version 3.11.7 to 4.1.0 to take advantage of new features and improvements. They requested guidance on upgrade procedures and a reliable source for downloading the required RPM. Zero downtime was a critical requirement to ensure uninterrupted operations during the upgrade process. Process: Step […]

Problem: The client was experiencing performance issues with a self-managed Cassandra database cluster hosted on Azure VMs. A recent surge in data traffic led to high CPU utilization, causing significant system slowness and increased latency. The environment utilized SSDs for storage, but earlier attempts at recommended SSD optimizations yielded no significant improvement. In light of […]