Abstract: According to one embodiment of the present invention, a system with a plurality of memories, generates a first filter associated with a first memory, and generates one or more second filters each associated with a corresponding memory. Each second filter is generated with a size at least partially accommodated within the storage capacity of the associated memory. The system determines absence of items from a set by selectively probing the generated filters in an ascending order of data access speed to the associated memories and aborts further probing for an item in response to a probe indicating that the item is absent from the set. Embodiments of the present invention further include a method and computer program product for testing set membership in substantially the same manners described above.

Abstract: According to one embodiment of the present invention, a system with a plurality of memories, generates a first filter associated with a first memory, and generates one or more second filters each associated with a corresponding memory. Each second filter is generated with a size at least partially accommodated within the storage capacity of the associated memory. The system determines absence of items from a set by selectively probing the generated filters in an ascending order of data access speed to the associated memories and aborts further probing for an item in response to a probe indicating that the item is absent from the set. Embodiments of the present invention further include a method and computer program product for testing set membership in substantially the same manners described above.

Abstract: Embodiments relate to payload storage format for storing data in support of an aggregation function. As an input is subject to aggregation, the input is evaluated to ascertain a payload format for the aggregation. It is understood that there is more than one payload format. An evaluation of the aggregation key is a factor in the initial payload format. If the key is an addition to an existing aggregation, the evaluation considers changing the format of the payload to address processing and/or memory efficiency for the aggregation. The evaluation and the format change takes place dynamically so that the aggregation may continue.

Abstract: Embodiments of the invention relate to payload storage format for storing data in support of an aggregation function. As an input is subject to aggregation, the input is evaluated to ascertain a payload format for the aggregation. It is understood that there is more than one payload format. An evaluation of the aggregation key is a factor in the initial payload format. If the key is an addition to an existing aggregation, the evaluation considers changing the format of the payload to address processing and/or memory efficiency for the aggregation. The evaluation and the format change takes place dynamically so that the aggregation may continue.

Abstract: A hybrid approach for performing a join in a database includes: obtaining a distribution of data values in a join column of an inner table; using the distribution, identifying one or more data ranges containing skew; for each data range identified as containing skew, performing, by the processor, the join operation using a skew specific join scheme; and for each data range not identified as containing skew, performing, by the processor, the join operation using a non-skew specific join scheme. One skew specific join scheme involves a compact array table, a highly populated array that represents the range of values that the inner table join column contains. One non-skew specific join scheme involves a compact hash table, an optimized hash table that allows high load factors with a small memory overhead. In combining multiple join techniques, joins may be performed more efficiently for skewed and non-skewed data.

Abstract: Partitioned join operations are performed between a first database object and a second database object by determining an agent group for an agent in response to the agent receiving rows of the second database object to process; partitioning the rows to determine a target hash table for each row and adding the partitioned rows to work performed by the agent group; and distributing the work for the group to agents of the group by assigning to a single agent all the rows associated with a particular hash table to perform a join operation on the assigned rows. Each partition is assigned a first counter value indicating an upper bound of a task id range that is most recently assigned to an agent in the agent group for processing, and a second counter value indicating the highest task id that has been processed for that partition.

Abstract: A first table has more than one key column, and a hash array is built for the table, which includes computing hash indices for respective rows of the first table based on more than one key column. Building the hash array also includes writing in the hash array for each row at a respective location in the hash array, wherein each location is indicated by each row's respective hash index computed from the more than one key column. The hash array is probed responsive to the second table. In the building of the hash array for the first table, the writing in the hash array for each row at a respective location in the hash array writes only one of the key columns as a single key field in the hash array for each row.

Abstract: A first request may be received to update a first set of values. The first set of values may be stored at a first location within a first data page of a database. The first location may be read-only. In response to the receiving of the first request, a first set of records may be inserted into a second data page. The first set of records may include the update of the first set of values. In response to the inserting, a forward pointer may be stored in the first data page that points to the first set of records on the second data page. One or more committed values may be identified on the second data page. In response to the identifying, the one or more committed values may be merged from the second data page to a third data page.

Abstract: A first request may be received to update a first set of values. The first set of values may be stored at a first location within a first data page of a database. The first location may be read-only. In response to the receiving of the first request, a first set of records may be inserted into a second data page. The first set of records may include the update of the first set of values. In response to the inserting, a forward pointer may be stored in the first data page that points to the first set of records on the second data page. One or more committed values may be identified on the second data page. In response to the identifying, the one or more committed values may be merged from the second data page to a third data page.

Abstract: A first request may be received to update a first set of values. The first set of values may be stored at a first location within a first data page of a database. The first location may be read-only. In response to the receiving of the first request, a first set of records may be inserted into a second data page. The first set of records may include the update of the first set of values. In response to the inserting, a forward pointer may be stored in the first data page that points to the first set of records on the second data page. One or more committed values may be identified on the second data page. In response to the identifying, the one or more committed values may be merged from the second data page to a third data page.

Abstract: Embodiments of the invention relate to payload storage format for storing data in support of an aggregation function. As an input is subject to aggregation, the input is evaluated to ascertain a payload format for the aggregation. It is understood that there is more than one payload format. An evaluation of the aggregation key is a factor in the initial payload format. If the key is an addition to an existing aggregation, the evaluation considers changing the format of the payload to address processing and/or memory efficiency for the aggregation. The evaluation and the format change takes place dynamically so that the aggregation may continue.

Abstract: A first request may be received to update a first set of values. The first set of values may be stored at a first location within a first data page of a database. The first location may be read-only. In response to the receiving of the first request, a first set of records may be inserted into a second data page. The first set of records may include the update of the first set of values. In response to the inserting, a forward pointer may be stored in the first data page that points to the first set of records on the second data page. One or more committed values may be identified on the second data page. In response to the identifying, the one or more committed values may be merged from the second data page to a third data page.

Abstract: A method for storing database information includes storing a table having data values in a column major order. The data values are stored in a list of blocks. The method also includes assigning a tuple sequence number (TSN) to each data value in each column of the table according to a sequence order in the table. The data values that correspond to each other across a plurality of columns of the table have equivalent TSNs. The method also includes assigning each data value to a partition based on a representation of the data value. The method also includes assigning a tuple map value to each data value. The tuple map value identifies the partition in which each data value is located.

Abstract: A method for storing database information includes storing a table having data values in a column major order. The data values are stored in a list of blocks. The method also includes assigning a tuple sequence number (TSN) to each data value in each column of the table according to a sequence order in the table. The data values that correspond to each other across a plurality of columns of the table have equivalent TSNs. The method also includes assigning each data value to a partition based on a representation of the data value. The method also includes assigning a tuple map value to each data value. The tuple map value identifies the partition in which each data value is located.

Abstract: Embodiments relate to data shuffling by logically rotating processing nodes. The nodes are logically arranged in a two or three dimensional matrix. Every time two of the nodes in adjacent rows of the matrix are aligned, adjacent nodes exchange data. The positional alignment is a logical alignment of the nodes. The nodes are logically arranged and rotated, and data is exchanged in response to the logical rotation.

Abstract: A method includes setting, by an update processor, a write latch in a first data structure associated with an object. The first data structure is copied to a storage structure. A history tuple sequence number (TSN) of the first data structure is set to point to a TSN of the copied first data structure. The version identifier is set to point to a transaction identification for the object. Data portions are updated for the first data structure. The version identifier is read from the first data structure. It is determined whether the version identifier of the first data structure is visible for a transaction including isolation requirements. If version identifier of the first data structure is visible, the first data structure is accessed and it is determined whether the version identifier of the first data structure changed since starting the transaction.

Abstract: Embodiments relate to data shuffling by logically rotating processing nodes. The nodes are logically arranged in a two or three dimensional matrix. Every time two of the nodes in adjacent rows of the matrix are positionally aligned, these adjacent nodes exchange data. The positional alignment is a logical alignment of the nodes. The nodes are logically arranged and rotated, and data is exchanged in response to the logical rotation.

Abstract: Embodiments include a method and computer program product for encoding data while it is being processed as part of a query is provided. The method includes receiving a query request and determining a set of values associated with data to be encoded for completing the query request. The method also includes encoding those values such that any subsequent processing operations can be performed on the encoded values to complete the requested query. After performing the subsequent processing operations to complete the requested query, each value is decoded back to its original value.

Abstract: A method includes performing a lookup using a key into a root node of a multi-tier data structure, to find a partition for performing an insert. A lookup for the key is performed on a first level index that is part of a linked data structure. A payload or reference is added to the linked data structure based on data structure criterion, otherwise the key and the payload are added to the linked data structure if the key is not found. A new first level index is created and added to the linked data structure upon the linked data structure remaining unchanged. The key and the payload or reference are added to the new index. Based on merge criterion, a new second level index is created and a portion of content from selected first level and second level indexes are merged for combining into the new second level index.

Abstract: A method includes performing, by a data structure processor, concurrent read and write operations into a hierarchical data structure. Writers acquire latches on the hierarchical data structure elements that the latches modify. The hierarchical data structure elements are directly accessed by readers without acquiring latches. A modify operation is executed by a writer for one or more levels of the hierarchical data structure. When removed portions of the hierarchical data structure are no longer referenced, tracking is performed by use of a combination of a global state value and a copied local state value. The global state value transitions through a non-repeating sequence of values. No longer referenced portions of the hierarchical data structure are tagged with the current global state value.