Snowflake Inc.

Xinzhu Cai

Florian Andreas Funke

Jiaqi Yan

Selcuk Aya

Bowei Chen

Muthunagappan Muthuraman

Prateek Gaur

Zhuo Peng

Dmitry A Lychagin

Mengran Wang

The subject technology receives a query, the query referencing a unified representation for structured type data and semi-structured type data, the unified representation being provided in storage and in memory during query processing, the unified representation comprising a set of structured type fields that include a set of semi-structured typed fields that enables type safety and enforcement for the set of structured type fields, and flexibility for the set of semi-structured typed fields in a same column, the unified representation in storage including type information for the semi-structured type data as part of the semi-structured type data, the unified representation being utilized for structured type data and semi-structured type data. The subject technology processes the query using the unified representation stored in the memory, the unified representation providing performance parity between structured type data and semi-structured type data.

Unified structured and semi-structured data types in database systems

Provided herein are systems and methods for handling build-side skew. For example, a method includes computing a plurality of hash values for a join operation. The join operation uses a corresponding plurality of row sets. The plurality of hash values are sampled to detect a frequent hash value. A build-side row set is partitioned using the frequent hash value to generate a partitioned build-side row set. The build-side row set is selected from the plurality of row sets. The partitioned build-side row set is distributed to a plurality of hash-join-build (HJB) instances executing at a corresponding plurality of servers.

Build-side skew handling for hash-partitioning hash joins

In one aspect, a computer-implemented method includes detecting, by a server includes one or more processors, a request to perform a hash join operation on a data structure stored in a data storage device, forming a hash lookup dictionary based on lookup results in a hash table, storing the hash lookup dictionary in a cache, and probing, during a probing phase of the hash join operation, the cache.

Smart scan hash join optimization

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San Mateo, CA, United States of America

Xinzhu Cai