When you code a SQL script that must run on PostgreSQL or YugabyteDB, you may want to set additional... Tagged with yugabytedb, postgres, distributed, database.

Franck Pachot

27.01.2025

ESR (Equality, Sort, Range) rule for YugabyteDB indexes - DEV Community

TL;DR: To make developers' lives easier, MongoDB has documented a simple rule for creating an... Tagged with yugabytedb, postgres, index, mongodb.

Franck Pachot

25.01.2025

Indexing for NOT EQUAL (<>,!=) in YugabyteDB, PostgreSQL, Oracle Database, SQL Server, and MongoDB - DEV Community

Indexing for Not-Equal in YugabyteDB Indexing for Not-Equal in PostgreSQL Indexing for Not-Equal in... Tagged with mongodb, oracle, postgres, yugabytedb.

Franck Pachot

22.01.2025

PostgreSQL 15 Compatibility in YugabyteDB 2.25: Top 15 Features! - DEV Community

The latest YugabyteDB preview release supports PostgreSQL 15. This represents a significant upgrade... Tagged with yugabytedb, postgres, distributed, sql.

Franck Pachot

21.01.2025

PostgreSQL Synchronized Sequential Scans and LIMIT without an ORDER BY - DEV Community

TL;DR: if you want predictable results with LIMIT or FETCH FIRST in any database, you need an ORDER... Tagged with postgres, sql, database, fullscan.

Franck Pachot

18.01.2025

Aggregates with NULL: count(), min(), max(), sum() - DEV Community

In the previous blog, I explained that a NULL in a column indicates an unknown value rather than a... Tagged with postgres, sql, database, yugabytedb.

Franck Pachot

17.01.2025

What does NULL mean in an OUTER JOIN? ("unknown" vs. "not exists") - DEV Community

In a previous post, I briefly mentioned that I consider a NULL in SQL databases as an existing but... Tagged with yugabytedb, distributed, postgres, sql.

Franck Pachot

15.01.2025

PostgreSQL plan_cache_mode - DEV Community

Here is a small test case to demonstrate plan_cache_mode, a PostgreSQL 12 feature available in... Tagged with yugabytedb, postgres, distributed, sql.

Franck Pachot

15.01.2025

could not serialize access due to concurrent update - DEV Community

The following error message from YugabyteDB may not be clear if you don't know how isolation levels...

Franck Pachot

13.01.2025

Unique Index on NULL Values in SQL & NoSQL - DEV Community

NoSQL behavior: MongoDB SQL behavior: PostgreSQL and YugabyteDB A mix of both: Oracle Database You... Tagged with postgres, oracle, mongodb, yugabytedb.

Franck Pachot

09.01.2025

Large IntentsDB MemTable with Many Small SST Files - DEV Community

An SQL transaction comprises many sequential reads and writes that affect different objects. These... Tagged with yugabytedb, distributed, postgres, database.

Franck Pachot

04.01.2025

Index Filtering in PostgreSQL and YugabyteDB (Index Scan instead of Index Only Scan) - DEV Community

This is inspired by Henrietta Dombrovskaya's recent post (Can we use this index, please? – Why not?),... Tagged with yugabytedb, postgres, distributed, database.

Franck Pachot

03.01.2025

Aurora DSQL: How it Compares to YugabyteDB - DEV Community

This was originally posted on the Yugabyte blog and details the Aurora DSQL Disaggregated... Tagged with yugabytedb, postgres, distributed, database.

Franck Pachot

30.12.2024

More details in pg_locks for YugabyteDB - DEV Community

One benefit of Wait-on-Conflict concurrency control, also known as pessimistic locking, is its... Tagged with yugabytedb, distributed, postgres, database.

Franck Pachot

28.12.2024

Document data modeling to avoid write skew anomalies - DEV Community

In a previous post, I explained that a serializable isolation level is not the only solution to avoid... Tagged with yugabytedb, distributed, postgres, json.

Franck Pachot

26.12.2024

When to replace IN() with EXISTS() - correlated and uncorrelated subqueries - DEV Community

If someone suggests rewriting your SQL query to use EXISTS instead of an IN subquery without... Tagged with yugabytedb, distributed, postgres, database.

Franck Pachot

20.12.2024

Referential integrity In The Absence Of Foreign Key - DEV Community

Aurora DSQL does not support Foreign Keys. How can you ensure referential integrity? It's often... Tagged with aws, aurora, dsql, database.

Franck Pachot

18.12.2024

2024.2: Faster with Shared Memory Between PostgreSQL and TServer Layers - DEV Community

In the latest YugabyteDB Long Term Support release (2024.2), the parameter... Tagged with yugabytedb, distributed, sql, database.

Franck Pachot

17.12.2024

Multi-Region Distributed SQL Transaction Latency - DEV Community

All distributed systems have trade-offs. Aurora DSQL uses Optimistic Concurrency Control and,... Tagged with aws, aurora, dsql, database.

Franck Pachot

16.12.2024

Global Secondary Indexes in Distributed SQL - DEV Community

In contrast to sharding (Aurora Limitless), which employs only local indexes, distributed SQL (Aurora...

Franck Pachot

14.12.2024

Optimistic Concurrency Control: Alice and Bob Couldn't Sit Together 🙁 - DEV Community

Alice and Bob want to go to the cinema together and sit next to each other. However, each will book...

Franck Pachot

12.12.2024

Joins, Scale, and Denormalization - DEV Community

In database design, denormalization is often glorified as a necessary step to improve performance,... Tagged with aws, postgres, aurora, dsql.

Franck Pachot

11.12.2024

DynamoDB-style Limits for Predictable Performance - DEV Community

I compare Aurora DSQL to DynamoDB rather than other SQL databases. One reason DynamoDB ensures... Tagged with aws, postgres, distributed, database.

Franck Pachot

09.12.2024

Aurora DSQL - Simple Inserts from an AWS CloudShell - DEV Community

My first test of Aurora DSQL focuses on read and write latency using an existing Java application... Tagged with aws, aurora, dsql, yugabytedb.

Franck Pachot

07.12.2024

Aurora DSQL: Create a Serverless Cluster and Connect with PostgreSQL Client - DEV Community

A Distributed SQL database service was announced at AWS re:Invent 2024 and is currently available in... Tagged with aws, postgres, distributed, sql.

Franck Pachot

04.12.2024

Amazon Aurora DSQL: Which PostgreSQL Service Should I Use on AWS ? - DEV Community

The Amazon Aurora innovations announced at re:Invent 2024 may leave you feeling overwhelmed when... Tagged with aws, distributed, database, yugabytedb.

Franck Pachot

01.12.2024

YugabyteDB MVCC and Updates: columns vs. JSON - DEV Community

YugabyteDB employs Multi-Version Concurrency Control (MVCC) to store all versions of table rows... Tagged with yugabytedb, distributed, postgres, database.

Franck Pachot

01.12.2024

Aurora Limitless - Sequences - DEV Community

Sequences are commonly used in SQL to generate unique numbers of small size and clustered to minimize... Tagged with aws, postgres, sharded, database.

Franck Pachot

29.11.2024

Aurora Limitless - Global Consistency (ACID) - DEV Community

The features discussed in previous posts of this series are comparable to other database-sharding... Tagged with aws, postgres, sharded, database.

Franck Pachot

29.11.2024

Aurora Limitless - Collocation (and porting PgBench) - DEV Community

Many people believe that implementing sharding on PostgreSQL-compatible databases ensures complete... Tagged with aws, postgres, sharded, database.

Franck Pachot

28.11.2024

Aurora Limitless - Reference Tables - DEV Community

In a previous post in this series, we discussed the limitations of database sharding. The data model... Tagged with aws, postgres, sharded, database.

Franck Pachot

27.11.2024

Aurora Limitless - Resharding - DEV Community

Re-sharding to scale out can be operationally complex when using database sharding. However, Aurora... Tagged with aws, postgres, sharded, database.

Franck Pachot

26.11.2024

No Gap Ordered Numbering in SQL: A Unique Index to Serialize In Read Committed - DEV Community

If you require a no-gap numbering system, using a sequence is not an option (see reasons here).... Tagged with yugabytedb, distributed, postgres, database.

Franck Pachot

26.11.2024

Aurora Limitless - SQL Limitations - DEV Community

It is important to clarify that Aurora Limitless is not a single distributed SQL database. Instead,... Tagged with aws, postgres, sharded, database.

Franck Pachot

26.11.2024

Aurora Limitless - Single and Multi-Shard Scan - DEV Community

I have created a sharded table and will examine the execution plan for point and range queries.... Tagged with aws, postgres, sharded, database.

Franck Pachot

25.11.2024

Aurora Limitless - Connection - DEV Community

The Aurora Limitless cluster provides a writer and reader endpoint: There's also a endpoint for the... Tagged with aws, aurora, sharded, database.

Franck Pachot

25.11.2024

Aurora Limitless - Sharded Table - DEV Community

In the previous posts, I created the 16 ACU cluster, which consists of two routers and two shards.... Tagged with aws, postgres, sharded, database.

Franck Pachot

25.11.2024

Aurora Limitless - Creation - DEV Community

Announced last year at re:Invent 2023, Aurora Limitless (PostgreSQL compatible) is available in... Tagged with aws, postgres, distributed, aurora.

Franck Pachot

20.11.2024

Achieving Precise Clock Synchronization on AWS - DEV Community

To achieve scalability, a distributed database must apply read and write operations without...

home›Franck Pachot›Software

Franck Pachot - Software

⛔ ORDER BY in Subquery - DEV Community

set parameter if exists - DEV Community

ESR (Equality, Sort, Range) rule for YugabyteDB indexes - DEV Community

Indexing for NOT EQUAL (<>,!=) in YugabyteDB, PostgreSQL, Oracle Database, SQL Server, and MongoDB - DEV Community

PostgreSQL 15 Compatibility in YugabyteDB 2.25: Top 15 Features! - DEV Community

PostgreSQL Synchronized Sequential Scans and LIMIT without an ORDER BY - DEV Community

Aggregates with NULL: count(), min(), max(), sum() - DEV Community

What does NULL mean in an OUTER JOIN? ("unknown" vs. "not exists") - DEV Community

PostgreSQL plan_cache_mode - DEV Community

could not serialize access due to concurrent update - DEV Community

Unique Index on NULL Values in SQL & NoSQL - DEV Community

Large IntentsDB MemTable with Many Small SST Files - DEV Community

Index Filtering in PostgreSQL and YugabyteDB (Index Scan instead of Index Only Scan) - DEV Community

Aurora DSQL: How it Compares to YugabyteDB - DEV Community

More details in pg_locks for YugabyteDB - DEV Community

Document data modeling to avoid write skew anomalies - DEV Community

When to replace IN() with EXISTS() - correlated and uncorrelated subqueries - DEV Community

Referential integrity In The Absence Of Foreign Key - DEV Community

2024.2: Faster with Shared Memory Between PostgreSQL and TServer Layers - DEV Community

Multi-Region Distributed SQL Transaction Latency - DEV Community

Global Secondary Indexes in Distributed SQL - DEV Community

Optimistic Concurrency Control: Alice and Bob Couldn't Sit Together 🙁 - DEV Community

Joins, Scale, and Denormalization - DEV Community

DynamoDB-style Limits for Predictable Performance - DEV Community

Aurora DSQL - Simple Inserts from an AWS CloudShell - DEV Community

Aurora DSQL: Create a Serverless Cluster and Connect with PostgreSQL Client - DEV Community

Amazon Aurora DSQL: Which PostgreSQL Service Should I Use on AWS ? - DEV Community

YugabyteDB MVCC and Updates: columns vs. JSON - DEV Community

Aurora Limitless - Sequences - DEV Community

Aurora Limitless - Global Consistency (ACID) - DEV Community

Aurora Limitless - Collocation (and porting PgBench) - DEV Community

Aurora Limitless - Reference Tables - DEV Community

Aurora Limitless - Resharding - DEV Community

No Gap Ordered Numbering in SQL: A Unique Index to Serialize In Read Committed - DEV Community

Aurora Limitless - SQL Limitations - DEV Community

Aurora Limitless - Single and Multi-Shard Scan - DEV Community

Aurora Limitless - Connection - DEV Community

Aurora Limitless - Sharded Table - DEV Community

Aurora Limitless - Creation - DEV Community

Achieving Precise Clock Synchronization on AWS - DEV Community

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