Methods and systems for optimizing queries in a multi-tenant store

A system to optimize database queries for a database system,

• wherein the system comprises:
• a processor and a memory;
• a communications interface to the database system, wherein the database system includes both a relational data store and a non-relational data store implemented therein;
• a request processor to receive a request at the host system for a database
• system, the request specifying data for retrieval from the database system;
• a customer schema processor to retrieve, based on the request, one or more locations of the data for retrieval;
• a query layer agent to generate a database query based on the request, wherein the database query specifies a plurality of data elements for retrieval, the plurality of data elements including a first portion of the data residing within a non-relational data store and a second portion of the data residing within a relational data store;
• a query optimizer to optimize the database query to include a join operation specifying a plurality of sub-queries to join the first portion of the data and the second portion of the data into a joined data set responsive to the request;
• wherein the query optimizer is to further:
• (i) identify a first sub-query to a table within the relational data store, corresponding to the first portion of the data for retrieval, (ii) identify a second sub-query to the non-relational data store corresponding to the second portion of the data for retrieval, (iii) replicate the table within the relational data store to the non-relational data store, and (iv) generate the optimized database query with one or more sub-queries to fetch both the first portion of the data for retrieval and the second portion of the data for retrieval from the non-relational data store;
• and
• wherein the query optimizer to (iii) replicate the table within the relational data store to the non-relational data store comprises the query optimizer replicating the table based on a policy to replicate a smaller dataset from its primary location to a location having the larger dataset in fulfillment of the replication;
• and
• wherein the query layer agent is to execute the optimized database query against the database system to retrieve the data.

Non-transitory computer readable storage media having instructions stored thereupon that, when executed by a processor of a database system, the instructions cause the database system to optimize database queries for the database system by performing operations comprising:

• receiving a request at a host system for the database system, the request specifying data for retrieval from the database system;
• retrieving, based on the request via the host system, one or more locations of the data for retrieval;
• generating, at the host system, a database query based on the request, wherein the database query specifies a plurality of data elements for retrieval, the plurality of data elements including a first portion of the data residing within the non- relational data store and a second portion of the data residing within the relational data store;
• optimizing the database query to include a join operation specifying a plurality of sub-queries to join the first portion of the data and the second portion of the data into a joined data set responsive to the request;
• wherein optimizing the database query further includes:
• (i) identifying a first sub-query to a table within the relational data store corresponding to the first portion of the data for retrieval, (ii) identifying a second sub-query to the non-relational data store corresponding to the second portion of the data for retrieval, (iii) replicating the table within the relational data store to the non-relational data store, and (iv) generating the optimized database query with one or more sub-queries to fetch both the first portion of the data for retrieval and the second portion of the data for retrieval from the non-relational data store;
• wherein optimizing the database query by (iii) replicating the table within the relational data store to the non-relational data store further comprises optimizing the database query based on a policy to replicate a smaller dataset from its primary location to a location having the larger dataset in fulfillment of the replication;
• and
• executing the optimized database query against the database system to retrieve the data.