What is Resident memory?
Verified 5 August 2026
Vector search systems conventionally hold their codes in memory, making resident memory linear in corpus size and putting a hard economic ceiling on index growth — a billion float vectors would need a terabyte of RAM.
Designs that page most of the index from disk and keep only a compact navigational structure in memory break that linear relationship, which is why resident-memory strategy is one of the more closely held parts of any vector search engine.
For a buyer the practical question is not which strategy a provider uses but whether the pricing reflects one that works — an engine paying for linear RAM growth has to charge for it eventually.
Common questions
What is Resident memory?
Resident memory is the portion of an index that must stay in RAM to serve queries, and it is usually what caps how large an index can economically grow.
How does Resident memory work in practice?
Designs that page most of the index from disk and keep only a compact navigational structure in memory break that linear relationship, which is why resident-memory strategy is one of the more closely held parts of any vector search engine.
See it working
The free tier is 10,000 requests a month with no card — enough to test any of this against your own queries.