This document discusses Flipkart's search architecture and how it addresses challenges for e-commerce search. It has a diverse catalog of 13 million products across 900 categories. It needs high performance with 99.99% availability and 1000 queries per second. There are also high rates of updates. Solutions discussed include caching, external source fields for sorting/faceting/filtering, and relevance optimizations. Caching improves performance 10-50x by caching results. External fields help with updates and partitioning. Relevance is tuned using boosts, user feedback, and query classification.