Merge pull request #5748 from Teggy/main

Add CIDR 2024 paper on UDF inlining/decorrelation

Author: szarnyasg

_science/2024-01-14-dear-udfs.md

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+---
+layout: post
+title: "Dear User-Defined Functions, Inlining isn't working out so great for us. Let's try batching to make our relationship work. Sincerely, SQL"
+author: "Kai Franz, Sam Arch, Denis Hirn, Torsten Grust, Todd C. Mowry, Andy Pavlo"
+thumb: "/images/science/thumbs/cidr-2024.svg"
+image: "/images/science/thumbs/cidr-2024.png"
+excerpt: ""
+tags: ["Paper"]
+---
+
+[Paper (PDF)](https://www.cidrdb.org/cidr2024/papers/p13-franz.pdf)
+
+Venue: CIDR 2024
+
+## Abstract
+
+SQL's user-defined functions (UDFs) allow developers to express complex
+computation using procedural logic. But UDFs have been the bane of database
+management systems (DBMSs) for decades because they inhibit optimization
+opportunities, potentially slowing down queries significantly. In
+response, batching and inlining techniques have been proposed to enable
+effective query optimization of UDF calls within SQL. Inlining is now
+available in a major commercial DBMS. But the trade-offs between both
+approaches on modern DBMSs remain unclear. We evaluate and compare UDF
+batching and inlining on enterprise and open-source DBMSs using a
+state-of-the-art UDF-centric workload. We observe the surprising result
+that although inlining is better on simple UDFs, batching outperforms
+inlining by up to 93.4× for more complex UDFs because it makes it easier
+for a DBMS’s query optimizer to decorrelate subqueries. We propose a
+hybrid approach that chooses batching or inlining to achieve the
+best performance.