Abstract: A protocol for implementing ACID transactions that provides snapshot isolation in a distributed setting that does not require synchronized clocks is described. The protocol ensures at commit time that transactions touching common objects do not commit out of order. The protocol can be used in the context of a distributed data lake built on an object store in which clients can transactionally add or remove objects from logical tables.

Abstract: Techniques for storage optimization in a distributed object store are described. A storage optimization service of a provider network monitors changes to data objects in a distributed object store that are part of a data lake and are referenced by a table index. The storage optimization service determines whether particular storage optimizations involving the data objects would be beneficial, prioritizes the ordering of these optimizations with a focus on performing impactful optimizations first, while intelligently scheduling the optimizations to avoid overutilization of available resources.

Abstract: Techniques for using tree data structures to maintain a transactionally consistent set with support for time-travel queries are described. When a transaction commits, a new version of the tree data structure is created using a copy-on-write based method such that the tree shares internal nodes with previous trees to save space. This approach may be used in the implementation of a transactional data catalog in which the files that make up a table are stored in a transactional set.

Abstract: Techniques for implementing systems using transactional version sets are described. Transactional version sets or t-sets include a collection of elements, each having a collection of metadata. A t-set is transactional in that a sequence of updates to one or more t-sets are made within an atomic transaction. A t-set is versioned since each committed transaction that updates it produces a new timestamped version that can be accessed via time-travel queries.

Abstract: A data transformation system includes a schema inference module and an export module. The schema inference module is configured to dynamically create a cumulative schema for objects retrieved from a first data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. Dynamically creating the cumulative schema includes, for each object of the retrieved objects, (i) inferring a schema from the object and (ii) selectively updating the cumulative schema to describe the object according to the inferred schema. The export module is configured to output the data of the retrieved objects to a data destination system according to the cumulative schema.

Abstract: A method of operating a data analysis system includes retrieving objects from a data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. The method further includes dynamically creating a cumulative schema by, for each object of the retrieved objects: (i) inferring a schema from the object based on the metadata of the object and inferred data types of elements of the data of the object, (ii) creating a unified schema, wherein the unified schema describes both (a) the object described by the inferred schema and (b) a cumulative set of objects described by the cumulative schema, and (iii) storing the unified schema as the cumulative schema. The method further includes exporting the data of each of the retrieved objects to a data warehouse.

Abstract: A method of operating a query system includes retrieving objects from a data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. The method further includes dynamically creating a cumulative schema. The dynamically creating includes, for each object of the retrieved objects, (i) inferring a schema from the object based on the metadata of the object and inferred data types of elements of the data of the object, (ii) creating a unified schema, and (iii) storing the unified schema as the cumulative schema. The unified schema describes both (a) the object described by the inferred schema and (b) a cumulative set of objects described by the cumulative schema. The method further includes storing the data of each of the retrieved objects in a storage service.

Abstract: A data transformation system includes a schema inference module and an export module. The schema inference module is configured to dynamically create a cumulative schema for objects retrieved from a first data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. Dynamically creating the cumulative schema includes, for each object of the retrieved objects, (i) inferring a schema from the object and (ii) selectively updating the cumulative schema to describe the object according to the inferred schema. The export module is configured to output the data of the retrieved objects to a data destination system according to the cumulative schema.

Abstract: A data transformation system includes a schema inference module and an export module. The schema inference module is configured to dynamically create a cumulative schema for objects retrieved from a first data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. Dynamically creating the cumulative schema includes, for each object of the retrieved objects, (i) inferring a schema from the object and (ii) selectively updating the cumulative schema to describe the object according to the inferred schema. The export module is configured to output the data of the retrieved objects to a data destination system according to the cumulative schema.

Abstract: A method of operating a data analysis system includes retrieving objects from a data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. The method further includes dynamically creating a cumulative schema by, for each object of the retrieved objects: (i) inferring a schema from the object based on the metadata of the object and inferred data types of elements of the data of the object, (ii) creating a unified schema, wherein the unified schema describes both (a) the object described by the inferred schema and (b) a cumulative set of objects described by the cumulative schema, and (iii) storing the unified schema as the cumulative schema. The method further includes exporting the data of each of the retrieved objects to a data warehouse.

Abstract: A data transformation system includes a schema inference module and an export module. The schema inference module is configured to dynamically create a cumulative schema for objects retrieved from a first data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. Dynamically creating the cumulative schema includes, for each object of the retrieved objects, (i) inferring a schema from the object and (ii) selectively updating the cumulative schema to describe the object according to the inferred schema. The export module is configured to output the data of the retrieved objects to a data destination system according to the cumulative schema.

Abstract: A distributed balanced tree having a plurality of nodes distributed across a plurality of servers is accessed. Version information associated with a node of the distributed balanced tree is retrieved. Validity of a lookup transaction performed on the balanced tree is determined by verifying a version value of only the leaf node accessed during the lookup operation against the retrieved version information.

Abstract: A method of operating a query system includes retrieving objects from a data source. Each of the retrieved objects includes (i) data and (ii) metadata describing the data. The method further includes dynamically creating a cumulative schema. The dynamically creating includes, for each object of the retrieved objects, (i) inferring a schema from the object based on the metadata of the object and inferred data types of elements of the data of the object, (ii) creating a unified schema, and (iii) storing the unified schema as the cumulative schema. The unified schema describes both (a) the object described by the inferred schema and (b) a cumulative set of objects described by the cumulative schema. The method further includes storing the data of each of the retrieved objects in a storage service.

Abstract: A method of operating a query system includes retrieving objects from a data source, wherein each of the retrieved objects includes (i) data and (ii) metadata describing the data. The method includes dynamically creating a cumulative schema by inferring a schema from each of the retrieved objects and merging the inferred schema with the cumulative schema. The method includes storing the data of each of the retrieved objects in a storage service. The method includes receiving, from a user, a query, and responding to the query based on data stored by the storage service.

Abstract: A distributed balanced tree having a plurality of nodes distributed across a plurality of servers is accessed. Version information associated with a node of the distributed balanced tree is retrieved. Validity of a lookup transaction performed on the balanced tree is determined by verifying a version value of only the leaf node accessed during the lookup operation against the retrieved version information.