Abstract: A method to perform an indexed geospatial search includes retrieving, by at least one hardware processor, a query specifying a geography data column and a constant geography object. A first plurality of hash functions of a first set of cells covering a surface associated with the geography data column is determined. A search index of a database including the geography data column is updated based on the first plurality of hash functions to obtain an updated search index. The query is executed on a reduced scan set of the database. The reduced scan set is based on the updated search index.

Abstract: Provided herein are systems and methods for indexed geospatial predicate search. An example method performed by at least one hardware processor includes decoding a query with a geospatial predicate. The geospatial predicate is configured between a geography data column and a constant geography object. The method further includes computing a first covering for a data value of a plurality of data values in the geography data column. The first covering includes a first set of cells in a hierarchical grid representation of a geography. The first set of cells represents a surface of the geography associated with the data value. A second covering is computed for the constant geography object. A determination is made on whether to prune at least one partition of a database organized into a set of partitions and including the geography data column based on a comparison between the first covering and the second covering.

Abstract: Provided herein are systems and methods for indexed geospatial predicate search. An example method performed by at least one hardware processor includes decoding a query with a geospatial predicate. The geospatial predicate is configured between a geography data column and a constant geography object. The method further includes computing a first covering for a data value of a plurality of data values in the geography data column. The first covering includes a first set of cells in a hierarchical grid representation of a geography. The first set of cells represents a surface of the geography associated with the data value. A second covering is computed for the constant geography object. A determination is made on whether to prune at least one partition of a database organized into a set of partitions and including the geography data column based on a comparison between the first covering and the second covering.

Abstract: A fault-tolerant node for synchronous heterogeneous database replication and a method for performing a synchronous heterogenous database replication at such a node are provided. A processor executes a computer program to generate a series of database transactions to be carried out at the fault-tolerant node. The fault-tolerant node comprises at least two relational database management systems, each of which are different relational database management system products, each implementing snapshot isolation between concurrent transactions. Each system comprises a database and a database management component. For each database transaction, operation instructions are provided concurrently to each of the systems to carry out operations on their respective databases and to provide respective responses. The responses generated by the systems either comprise an operation result or an exception.

Abstract: A fault-tolerant node for synchronous heterogeneous database replication and a method for performing a synchronous heterogenous database replication at such a node are provided. A processor executes a computer program to generate a series of database transactions to be carried out at the fault-tolerant node. The fault-tolerant node comprises at least two relational database management systems, each of which are different relational database management system products, each implementing snapshot isolation between concurrent transactions. Each system comprises a database and a database management component. For each database transaction, operation instructions are provided concurrently to each of the systems to carry out operations on their respective databases and to provide respective responses. The responses generated by the systems either comprise an operation result or an exception.

Abstract: A planetary wire-feeding mechanism has a left and right driving roll with hyperboloid profiles in a housing made up of two equal left and right cylinders, with an axis of rotation coinciding with the geometric axis of the electrode wire. The two cylinders contact one another and are joined detachably. In each of them there is shaped semi-cylindrical seats having parts with a common axis perpendicular to the geometric axis of the electrode wire and disposed in the plane of contacts between the two cylindrical parts. In the semi-cylindrical seats there are mounted two identical units, disposed in opposite directions, each unit having a base and two opposite legs, the legs of the two oppositely disposed units being interdigitated when they are mounted within the housing. Such units constitute supporting-guiding components upon which they are disposed on the right and left driving rolls.