WRITELOG is one of the common wait types found in the SQL Server. It is directly related to the speed and efficiency of writing transaction log stored in the file system. This ensures durability and data integrity. When WRITELOG waits are high, it usually indicates that SQL Server is spending too much time waiting for in-memory transaction log cache to be flushed to the transaction log file. This can slow down transactions and ripple across the entire workload. In this guide, we will explore what causes WRITELOG waits, how to identify the root bottlenecks, and practical ways to reduce their impact through configuration, hardware optimization, and workload tuning.
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Execution Plan is like a blueprint. SQL Server uses it to execute a DML query. As a DBA, understanding execution plans is like reading the X-ray of query performance. It exposes where SQL Server spent its time and resources, which indexes used or ignored, and area of performance bottlenecks.
In this article, you will go through how to analyze SQL Server execution plans, interpret key operators, and identify optimization opportunities.
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Did you ever face any scenario where you found no issues in CPU, memory, Disk IO or network, still some users are facing slow response and SQL Server has high ASYNC_NETWORK_IO wait type? At first glance, it may seem like SQL Server is the problem—but in reality, this wait type usually points outside the database engine. It occurs when SQL Server has results ready to send, but the client application (or the network in between) cannot consume the data fast enough. This may result-in query slowness, blocked sessions, and frustrated users.
In this article you will walk through what ASYNC_NETWORK_IO is when it occurs, simulate it and share some techniques to reduce them. Let's start.
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Last page insert contention is common in a busy SQL Server environment where multiple users are inserting data simultaneously in a table and that table has clustered index on an identity column. When multiple sessions try to add data in the same data page file, the data page becomes "hotspot". As a result, processes queue up to acquire access to the last page, which leads to latch contention, high wait times, and overall reduced performance. Understanding why last page insert contention arises and its mitigation techniques are crucial for handling workloads with rapid inserts.
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As DBAs, we all know how frustrating deadlocks can be. One moment everything looks fine, and the next, SQL Server decides to kill a perfectly good query just to break the deadlock cycle. Hunting down the cause often means digging through error logs, setting up Extended Events, and piecing together XML deadlock graphs that feel more like puzzles than solutions.
That is where sp_BlitzLock comes to the rescue. It takes the pain out of deadlock analysis by reading deadlock graphs for you and turning them into a clear, easy-to-understand report. Instead of spending hours trying to figure out who blocked whom, you get a straightforward breakdown of the queries, resources, and victims involved. In short, sp_BlitzLock makes a DBA’s life much easier when dealing with deadlocks.
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In the world of SQL Server, ensuring data consistency, and concurrency is critical — but it often comes with challenges like locking, blocking and deadlocking. These negatively impact on performance. As databases grow in size and usage, understanding how SQL Server handles concurrent data access becomes essential for any DBA.
In this first part of the series, we will dive deep into the core concepts of locks and blocks, explore how they work, and examine why they occur. Through real-world examples and practical scripts, this article aims to equip you with the knowledge to identify, analyze, and handle common blocking scenarios. Mastering these fundamentals will prepare you for the more complex topic of deadlocks, which we will cover in Part 2.
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As a human being, your SQL Server tries to express its pain point with you — but not in words. It whispers through wait stats, sending subtle signals when something is off. But, you have to learn how to decode these signals.
In this article, we will decode the most common SQL Server wait types—like CXPACKET, PAGEIOLATCH, and SOS_SCHEDULER_YIELD—and understand what they are quietly telling you about your server’s workload, health, and bottlenecks. If you have ever wondered why your queries slow down despite healthy hardware, the answer might just be in these whispers.
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As a DBA, you are often alert to the usual suspects—blocking, deadlocks, or long-running queries. But sometimes, performance issues creep in silently, and one of the quietest yet most impactful culprits is latch contention. Unlike locks, latches are lightweight synchronization primitives that protect internal memory structures. When these get overwhelmed, even the most well-tuned queries can slow to a crawl.
In this guide, you will explore what latch contention is, how it differs from locks, when it occurs, how to detect it, and most importantly—how to tune your system to minimize its impact. Whether you are running a high-throughput OLTP workload or managing a reporting environment, understanding latches could be the missing piece in your performance puzzle.
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In the world of SQL Server performance tuning, intuition is helpful—but data is essential. Without a solid performance baseline, DBAs are left guessing whether a system slowdown is an anomaly or just another busy working day. Creating a baseline gives you a point of comparison to understand what "normal" looks like for your SQL Server environment. This article will guide you through what to capture, how to capture it, and how to turn that information into actionable insight—so the next time someone says, "the database is slow", you will have data to prove or disprove it.
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In today’s data-driven environments, SQL Server performance is not just about fast queries, efficient indexes — it also heavily depends on how well your database communicates over the network. Whether it is a slow application response, timeout errors, or replication delays, the network often plays an invisible but critical role. As DBAs, we tend to focus on CPU, memory, and disk — yet overlooking network performance can leave significant bottlenecks unresolved.
This guide will walk you through essential network-related metrics, troubleshooting techniques, and tuning tips to ensure your SQL Server operates smoothly. Let’s decode what is happening between your servers — and keep the data flowing efficiently.
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