https://dasya.itu.dk/tags/query-optimizer/ Recent content in query optimizer on DASYA Hugo -- gohugo.io en-us © DASYA, IT University of Copenhagen Fri, 24 Jul 2026 00:00:00 +0000 https://dasya.itu.dk/for-students/proposals/current/mh-ai-db-workloads/ Fri, 24 Jul 2026 00:00:00 +0000 https://dasya.itu.dk/for-students/proposals/current/mh-ai-db-workloads/ BSc Thesis / MSc Thesis. The goal of this project is to use AI coding tools such as ChatGPT Codex and Claude Code together with optimization tools such as OpenEvolve to find innovative solutions for various database-y workloads, including: SIEM workloads, such as finding IP addresses in large security data sets String search workloads, such as finding substrings or evaluating regular expressions in large bodies of text Data analysis workloads, such as executing SQL queries over application logs The core idea is to find better statistics to summarize data partitions. https://dasya.itu.dk/for-students/proposals/archive/mh-charmaps/ Wed, 02 Jul 2025 00:00:00 +0000 https://dasya.itu.dk/for-students/proposals/archive/mh-charmaps/ MSc Thesis. Character maps in database systems are specialized data structures optimized for efficient string handling. Similar to Bloom filters, they allow quick checks for the presence of characters or substrings without full string comparisons. This makes them useful for accelerating string-related queries and improving overall search performance in databases. The goal of this project is to delve deeply into character maps: What strategies for building character maps exist, and how do they compare to Bloom filters and prefix trees (aka tries)? https://dasya.itu.dk/for-students/proposals/archive/mh-minmax-duckdb/ Wed, 02 Jul 2025 00:00:00 +0000 https://dasya.itu.dk/for-students/proposals/archive/mh-minmax-duckdb/ MSc Thesis. DuckDB stores data in a database file. The database file is split into partitions, and for each partition, DuckDB keeps statistics in the form of min-max summaries. Similar min-max summaries exist in Parquet files and many other database systems, such as Snowflake. Check out Lecture 8 of last semester’s Introduction to Database Systems course for a summary of min-max summaries (I can send the slide deck if needed). https://dasya.itu.dk/for-students/proposals/current/zk-datafarm/ Wed, 28 May 2025 00:00:00 +0000 https://dasya.itu.dk/for-students/proposals/current/zk-datafarm/ Query optimization is crucial for any data management system to achieve good performance. Recent advancements in AI have led academia and industry to investigate learning-based techniques in query optimization. In particular, many works propose replacing the cost model used during plan enumeration with a machine learning model that estimates the runtime of a plan. However, to build such a model lots of training data are required. In this context, training data comprise of query plans and their runtimes.