Abstract: An approach is provided for a thorough and clean way of handling graph overflows in graph execution on single instruction, multiple threads (SIMT) hardware with resumable graph support. The solution does not assume that the input and output fit in the buffers allocated in the SIMT hardware. The approach maintains state of the execution for each kernel and uses multiple iterations of graph execution, making progress in each iteration until all data items are processed through the graph on SIMT hardware. This iterative processing of the graph is transparent to the end user. For resumability, the approach treats buffers as circular buffers instead of serial buffers. With the help of counters, the approach keeps track of the start and end indexes of input and output buffers, thus achieving seamless graph resumability when re-execution is required for only a subset of kernels.

Abstract: An append operation is provided for using a plurality of threads on a plurality of streaming multiprocessors of a graphical processing unit. The append operation writes results into a result buffer. Executing the append operation comprises claiming, by each given thread within the plurality of threads having a result to write, a portion of a selected WCB, writing, by the given thread, the result to the portion of the selected WCB, and in response to a flush condition being met for the selected WCB, copying contents of the selected WCB to a result buffer.

Abstract: An append operation is provided for using a plurality of threads on a plurality of streaming multiprocessors of a graphical processing unit. The append operation writes results into a result buffer. Executing the append operation comprises claiming, by each given thread within the plurality of threads having a result to write, a portion of a selected WCB, writing, by the given thread, the result to the portion of the selected WCB, and in response to a flush condition being met for the selected WCB, copying contents of the selected WCB to a result buffer.

Abstract: Methods for automatic selection of degrees of parallelism for efficient execution of queries in a database system are performed by systems and devices. An incoming query associated with a query system is received and features of the incoming query are determined. A system state of the query system and a set of executing queries are also determined, along with a query state of each executing query in the set. At runtime of the incoming query, allocation of a degree of parallelism for executing the query is determined by calculating different possible execution times for the incoming query at least partially concurrently with the set of executing queries. Execution times are calculated for different parallel thread options and based on query features, system state, or query states of executing queries. The execution of the incoming query is initialized with the parallel thread option corresponding to a specific execution completion time.

Abstract: Methods for automatic selection of degrees of parallelism for efficient execution of queries in a database system are performed by systems and devices. An incoming query associated with a query system is received and features of the incoming query are determined. A system state of the query system and a set of executing queries are also determined, along with a query state of each executing query in the set. At runtime of the incoming query, allocation of a degree of parallelism for executing the query is determined by calculating different possible execution times for the incoming query at least partially concurrently with the set of executing queries. Execution times are calculated for different parallel thread options and based on query features, system state, or query states of executing queries. The execution of the incoming query is initialized with the parallel thread option corresponding to a specific execution completion time.

Abstract: Disclosed herein are system, method, and computer program product embodiments for populating a hash index and returning a handle to the hash index. An embodiment operates by determining, by at least one processor, during query optimization that a first database query has a query execution plan comprising a sub-query which executes N times a correlated predicate having an operator being one of equal and not equal to a base column. A cost of creating and probing the hash index N times and a cost of fully scanning the base column N times are compared based on the correlated predicate. Based on the comparing, it is determined whether to create on-demand a hash index.

Abstract: Disclosed herein are system, method, and computer program product embodiments for populating a hash index and returning a handle to the hash index. An embodiment operates by determining, by at least one processor, during query optimization that a first database query has a query execution plan comprising a sub-query which executes N times a correlated predicate having an operator being one of equal and not equal to a base column. A cost of creating and probing the hash index N times and a cost of fully scanning the base column N times are compared based on the correlated predicate. Based on the comparing, it is determined whether to create on-demand a hash index.