Teradata Us, Inc.

Snigdha Prasad

Nobul Reddy Goli

Karthik Sai Vakkalagadda

Arnab Roy

Sama Rajender Reddy

Dinesh Chengalpatu

Venkata Sai Prakash Reddy Sangu

Injamuri Krutika

A system and method for extending compression-aware aggregation logic to column partitioned database sources when an SQL query involves simple or complex aggregate expressions. The logic can be applied when there are multiple fields specified in a Group By clause, when a Group By clause includes an expression involving multiple columns from a column partitioned table, or when there is no Group By clause in the query. This logic extends the benefits of push-down aggregation to complex aggregate queries to build partially aggregated rows that can be directly added into an intermediate cache. For cases where the fields within aggregate expressions are themselves compressed, the aggregation techniques leverage the compression information of the aggregate fields. This aggregation mechanism can be applicable to compression techniques including run-length encoding (RLE), value list compression (VLC) and Presence, Delta on Mean (PDM) on columnar source tables such as Column Partitioned (CP) or Parquet tables.

Compression aware aggregations for queries with expressions

A method, apparatus, and computer program product for executing a relational database management system (RDBMS) in a computer system, wherein the RDBMS manages a relational database comprised of at least one column-partitioned base table storing data. Column values from at least one column of the column-partitioned base table are stored in one or more containers spread across one or more data blocks. Metadata comprising summarized information about the column values in the containers is stored in a metadata index subtable. A query with a filtering condition on the column is applied to the metadata index subtable before the column-partitioned base table is accessed, so that only qualified containers and data blocks are accessed, and unqualified containers and data blocks are eliminated, when responding to the query.

Optimizing performance using a metadata index subtable for columnar storage

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Hyderabad Telangana, India

Snigdha Prasad