At the risk of protesting too much in the shifting database landscape, NoSQL-based MongoDB has attempted to trash the competition by claiming PostgreSQL systems lack scalability to keep up with the demands of AI workloads.

CEO Chirantan Desai took the opportunity of largely positive [1]earnings results for the quarter ended Oct. 31 to make a couple of pointed remarks about the open source PostgreSQL database, which has climbed to the top in developer rankings in recent years.

Speaking to investment analysts, he said that while MongoDB had all the elements needed to be the right foundational platform for AI workloads, it was too early to say what might be the platform of choice.

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However, he said MongoDB had been winning work from AI-native companies, citing a customer that recently "switched from PostgreSQL to MongoDB because PostgreSQL could not just scale."

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MongoDB enjoyed a 23% spike in its share price on Tuesday morning after it beat investor forecasts and offered guidance above expectations for the period, which was the third quarter of its 2026 fiscal year. Revenue hit $628.3 million in Q3 FY 2026, up 19 percent on the same period last year. Losses from operations narrowed to $18.4 million from $27.9 million in the year-ago period.

Nonetheless, Desai may have reason to target PostgreSQL because the open source system first developed in the 1980s has been making moves on its turf.

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Document database MongoDB was trumpeted as the database for developers because it allows them to get building applications and create governance as they go, owing to its schema-less or schema-lite approach. It promises them speed and flexibility.

But by 2023, relational system PostgreSQL had become the [6]most popular database among professional developers in the Stack Overflow survey. In 2016, PostgreSQL overtook MongoDB in the DB-Engines ranking, which relies on various metrics including website citations, Google search trends, appearance in online technical discussions, and job ads.

Raimo Lenschow, analyst at Barclays Bank, challenged Desai on the point, asking about developer engagement against a "PostgreSQL-kind-of-narrative that happens a lot in [Silicon Valley]."

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Desai responded by citing a customer – a "super-high growth AI company" – which was "not able to scale with PostgreSQL... and they moved completely to MongoDB."

PostgreSQL has gained popularity on the back of database services available from the leading cloud vendors, which have been hit by user [8]concerns about reliability .

However, a bunch of PostgreSQL and near-compatible services with distributed back ends are available to address those concerns. These include CockroachDB, pgEdge, and YugabyteDB.

[9]Microsoft spins up Azure HorizonDB to take on distributed Postgres rivals

[10]Linux Foundation says yes to NoSQL via DocumentDB

[11]MongoDB rebuts claims it's not ready for business critical workloads

[12]MongoDB CEO says if AI hype were the dotcom boom, it is 1996

Meanwhile, PlanetScale, which made its name with a distributed MySQL service based on YouTube-developed relational database Vitess, has also launched a PostgreSQL service.

Microsoft has also recently [13]announced a distributed PostgreSQL database service – HorizonDB – designed to rival other hyperscaler systems and third-party RDBMSes such as CockroachDB and YugabyteDB. Claiming 100 percent compatibility with open source PostgreSQL, Microsoft said the database service available on Azure would implement a new storage layer that significantly improves performance, scalability, and availability of the database compared to its other PostgreSQL services. It rivals distributed PostgreSQL services from Google (AlloyDB) and AWS (Aurora DSQL).

To add even more into the mix, [14]Microsoft has launched a document database platform to rival MongoDB . DocumentDB is constructed on a relational PostgreSQL back end and can use FerretDB as a front-end interface with a document database protocol.

In the face of such competition, MongoDB has been forced to defend its system, not in terms of pure scalability, but [15]for its reliability for enterprise workloads , something it has long claimed it is ready for.

It's understandable that Desai is hitting out at the competition, but he might want to be careful about what he draws attention to. ®

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[1] https://investors.mongodb.com/news-releases/news-release-details/mongodb-inc-announces-third-quarter-fiscal-2026-financial

[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aS8bKgE-WcMOENZ5JmdtcgAAANY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0

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[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aS8bKgE-WcMOENZ5JmdtcgAAANY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[5] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aS8bKgE-WcMOENZ5JmdtcgAAANY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0

[6] https://devclass.com/2023/06/13/postgresql-now-top-developer-choice-ahead-of-mysql-according-to-massive-new-survey/

[7] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/databases&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aS8bKgE-WcMOENZ5JmdtcgAAANY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0

[8] https://www.theregister.com/2025/07/22/postgresql_hyperscalers_gartner/

[9] https://www.theregister.com/2025/11/19/microsoft_azure_horizondb/

[10] https://www.theregister.com/2025/08/25/linux_foundation_says_yes_to/

[11] https://www.theregister.com/2024/10/03/mongodb_business_critical_critics/

[12] https://www.theregister.com/2024/09/13/mongodb_ceo_says_if_ai/

[13] https://www.theregister.com/2025/11/19/microsoft_azure_horizondb/

[14] https://www.theregister.com/2025/01/27/microsoft_builds_open_source_document/

[15] https://www.theregister.com/2024/10/03/mongodb_business_critical_critics/

[16] https://whitepapers.theregister.com/