摘要:
Methods and apparatus, including computer program products, for block compression of tables with repeated values. In general, value identifiers representing a compressed column of data may be sorted to render repeated values contiguous, and block dictionaries may be generated. A block dictionary may be generated for each block of value identifiers. Each block dictionary may include a list of block identifiers, where each block identifier is associated with a value identifier and there is a block identifier for each unique value in a block. Blocks may have standard sizes and block dictionaries may be reused for multiple blocks.
摘要:
Innovations for adaptive compression and decompression for dictionaries of a column-store database can reduce the amount of memory used for columns of the database, allowing a system to keep column data in memory for more columns, while delays for access operations remain acceptable. For example, dictionary compression variants use different compression techniques and implementation options. Some dictionary compression variants provide more aggressive compression (reduced memory consumption) but result in slower run-time performance. Other dictionary compression variants provide less aggressive compression (higher memory consumption) but support faster run-time performance. As another example, a compression manager can automatically select a dictionary compression variant for a given column in a column-store database. For different dictionary compression variants, the compression manager predicts run-time performance and compressed dictionary size, given the values of the column, and selects one of the dictionary compression variants.
摘要:
Methods and apparatus, including computer program products, are provided for providing for processing calculation plans. In one aspect, there is provided a computer-implemented method. The method may include generating a calculation plan including a plurality of nodes; determining whether at least one of the nodes includes a function node; and compiling the function node into executable code to enable execution of the plurality of nodes including the function node at the database. Related apparatus, systems, methods, and articles are also described.
摘要:
A pattern can be identified in at least part of a query whose definition is received in a query request. The identified pattern can be matched with a set of pre-defined patterns, each of which has associated therewith at least one pre-compiled query execution sub-component of a plurality of pre-compiled query execution sub-components retained in a library. A plan for executing the query can be generated, for example by incorporating the pre-compiled query execution sub-component associated with the matched pattern into the plan based on a pseudo code representation of the plan derived from the definition.
摘要:
The subject matter described herein relates to implementation of a dictionary in a column-based, in-memory database where values are not stored directly, rather, for each column, a dictionary is created with all distinct values. For each row, a reference to the corresponding value in the dictionary is stored. In one aspect, data is stored in a memory structure organized in a column store format defined by a plurality of columns and a plurality of rows. A dictionary for each column in the memory structure is generated. The dictionary has distinct values for each column. A reference to the dictionary is generated for each column in the memory structure. The dictionary and the reference to the dictionary are stored in the memory structure.
摘要:
Methods and apparatus, including computer program products, for block compression of tables with repeated values. In general, value identifiers representing a compressed column of data may be sorted to render repeated values contiguous, and block dictionaries may be generated. A block dictionary may be generated for each block of value identifiers. Each block dictionary may include a list of block identifiers, where each block identifier is associated with a value identifier and there is a block identifier for each unique value in a block. Blocks may have standard sizes and block dictionaries may be reused for multiple blocks.
摘要:
Inverted indexes for terms and for term separators are separately provided to minimize data redundancy. Search queries are parsed to identify terms and term separators, if any, and the corresponding inverted indexes are searched for responsive documents. Related apparatus, systems, techniques and articles are also described.
摘要:
Methods and apparatus, including computer program products, for compression of tables based on occurrence of values. In general, a number representing an amount of occurrences of a frequently occurring value in a group of adjacent rows of a column is generated, a vector representing whether the frequently occurring value exists in a row of the column is generated, and the number and the vector are stored to enable searches of the data represented by the number and the vector. The vector may omit a portion representing the group of adjacent rows. The values may be dictionary-based compression values representing business data such as business objects. The compression may be performed in-memory, in parallel, to improve memory utilization, network bandwidth consumption, and processing performance.
摘要:
Methods and apparatus, including computer program products, for block compression of tables with repeated values. In general, value identifiers representing a compressed column of data may be sorted to render repeated values contiguous, and block dictionaries may be generated. A block dictionary may be generated for each block of value identifiers. Each block dictionary may include a list of block identifiers, where each block identifier is associated with a value identifier and there is a block identifier for each unique value in a block. Blocks may have standard sizes and block dictionaries may be reused for multiple blocks.
摘要:
A system, medium, and method including modifying a graphical view representation of a first table of a set of data, the first table having at least a first column subject to changes in value; modifying a graphical view representation of a second table of a second set of data; determining a query operation of the view representations of the first table and second table; aggregating values of the view representation of the result of the query operation having a same key; determining, based on the aggregated values, values for the first column of the view representation of the first table; and providing an output of the values for the first column of the view representation of the first table, the output values including changed values.