Parallel execution of merge operations

A system comprising:

• a memory having computer readable instructions;
• and
• one or more processing devices for executing the computer readable instructions, the computer readable instructions comprising:
• receiving a structured query language (SQL) database command at a processing device, the processing device configured to manage a table space of a relational database, the database command including a merge statement configured to instruct the processing device to perform a merge operation, wherein the merge statement includes one or more local predicates;
• identifying a group of target records from the merge statement based on the one or more local predicates specifying the group of target records, and associating each target record with one of a plurality of portions of the table space, wherein the group of target records are identified based on the one or more local predicates;
• in response to determining that the group of target records having been identified based on the one or more local predicates is associated with more than one portion of the table space, sorting the target records into a plurality of sub-groups, each sub-group associated with a different portion of the table space, wherein each target record includes a record identifier (RID) that indicates a location within a data page associated with a space map page;
• generating a sub-task associated with each sub-group, the sub-task prescribing aspects of performing the merge operation on an associated portion of the table space using an associated sub-group respective sub-group;
• and
• performing all of the sub-tasks in parallel.

A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processing device to cause the processing device to perform a method comprising:

• receiving a structured query language (SQL) database command at a processing device, the processing device configured to manage a table space of a relational database, the database command including a merge statement configured to instruct the processing device to perform a merge operation, wherein the merge statement includes one or more local predicates;
• identifying a group of target records from the merge statement based on the one or more local predicates specifying the group of target records, and associating each target record with one of a plurality of portions of the table space, wherein the group of target records are identified based on the one or more local predicates;
• in response to determining that the group of target records having been identified based on the one or more local predicates is associated with more than one portion of the table space, sorting the target records into a plurality of sub-groups, each sub-group associated with a different portion of the table space, wherein each target record includes a record identifier (RID) that indicates a location within a data page associated with a space map page;
• generating a sub-task associated with each sub-group, the sub-task prescribing aspects of performing the merge operation on an associated portion of the table space using an associated sub-group respective sub-group;
• and
• performing all of the sub-tasks in parallel.