Aggregation operations in a distributed database

A system, comprising:

• one or more memories;
• and
• one or more processors, the one or more processors configured to execute instructions stored in the one or more memories to:
• receive, at a distributed database that includes multiple database instances, a data-query including an aggregation clause on a first column of a table that is partitioned into shards according to a sharding criterion based on the first column such that all rows having a same value for the first column are included in a same shard, wherein the shards are distributed to the multiple database instances;
• receive, from at least some of the database instances, respective intermediate results, wherein each respective intermediate result received from a respective database instance that includes a respective shard is an aggregation of values of the first column in the respective shard;
• combine the respective intermediate results to obtain a combined result of the data-query;
• and
• output the combined result.

One or more non-transitory computer readable media storing instructions operable to cause one or more processors to perform operations comprising:

• receiving, at a distributed database that includes multiple database instances, a data-query including an aggregation clause on a first column of a table that is partitioned into shards according to a sharding criterion based on the first column such that all rows having a same value for the first column are included in a same shard, wherein the shards are distributed to the multiple database instances;
• receiving, from at least some of the database instances, respective intermediate results, wherein each respective intermediate result received from a respective database instance that includes a respective shard is an aggregation of values of the first column in the respective shard;
• combining the respective intermediate results to obtain a combined result of the data-query;
• and
• outputting the combined result.