German Strings for Faster Analytics

String handling is a significant performance bottleneck in analytical databases. Traditional approaches store strings as pointers to heap-allocated memory, causing cache misses and memory indirection overhead during scans and comparisons.

In this article, I explore "German strings" - an optimization technique used by modern analytical databases like DuckDB. The key insight is storing a prefix of the string inline within the pointer structure itself, enabling:

• Fast prefix comparisons without dereferencing pointers
• Better cache utilization by keeping frequently-accessed data together
• Reduced memory indirection for short strings that fit entirely inline

The technique gets its name from the Umbra database system developed in Germany, which pioneered this approach.

Originally published on the e6data engineering blog.