Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: An insertion of a record into a table that includes a primary key column and a second column that includes a global uniqueness constraint across all of a plurality of data partitions across which the table is split is initiated without checking that a value of the record in the second column is globally unique by contacting other partitions the one partition to which the record is to be added to. The insertion can be processed, at least in part by implementing a write lock on the one partition but without implementing a read lock on the other partitions. The write lock on the one partition can be released after the insertion is completed, after which the validity of the insertion can be verified, for example by examining the other parts and a delta partition corresponding to the table. The insertion can be undone if the insertion was not valid.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: A computer-implemented system and method for providing an historical view of a data record are disclosed. A data record is stored in main memory of a server computer. An instruction to update the data record is received, and the instruction to update the data record is executed to provide a most recent version of the data record. A history table is generated that includes a main table part that represents the most recent version of the data record after the data record is updated, and a history table part that represents one or more past versions of the data record before the data record is updated. The history table is stored in the main memory of the server computer.

Abstract: A join operation between split data tables includes providing reduction data from first partitions to each partition among second partitions. The reduction data serves to identify actual values in one of the second partitions that also occur in one of the first partitions. Global IDs are assigned. Translation lists including the global IDs are sent to the first partitions. Each first partition and each second partition create globalized lists which can then be combined to generate respective first and second compiled lists. The join operation can then be conducted on the first and second compiled lists.

Abstract: Systems and methods for using optimization techniques to construct a nearly optimal execution plan for an outer join query are disclosed. A query graph of the outer join query is constructed, by computing for each node the set of nodes influencing it, for each target node the set of its needed reducers, and predetermining the effects of all admissible moves in all possible sequences. The directed graph of all admissible move sequences is formed. An optimization process includes dynamically generating good estimations for the target distance of a search state. Some heuristics are disclosed for providing start solutions for the optimization process.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: A search query for a collection of electronic documents is parsed to identify one or more terms and such identified terms are associated with one or more languages (i.e., spoken languages such as English, German, Spanish, etc.). A terms inverted index and a language inverted index are accessed to identify documents responsive to the query. Related apparatus, systems, techniques and articles are also described.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: Systems and methods are provided for efficient calculation of sets of distinct results in an information retrieval service. A query is received having at least one requested attribute and one or more conditions. For each row identifier in a database table that matches the one or more conditions, a tuple of value identifiers having an entry for each requested attribute is calculated. A unique number is generated and assigned to the tuple for each distinct combination of the value identifiers. Duplicate entries in the tuple listing are identified and removed, so that a result set provides only distinct results.

Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: Methods and apparatus, including computer program products, for selection of rows and values from indexes with updates. In general, rows of an index may be associated with validity flags that indicate whether a row has been updated with an update inserted in a delta index; one scheme for value identifiers may be used for an index and another scheme for one or more delta indexes where all of the indexes are, to at least some extent, compressed according to dictionary-based compression; and multiple delta indexes may be used in alternation such that one delta index may accept updates while another is being updated. The delta indexes may also have validity flags and all updates, such as modifications of values, deletion of records, and inserting of new records may be handled as updates accepted by one or more delta indexes.

Abstract: A system and method for executing semijoin reductions on outer join operations are presented. Tuple lists are created based on a query. A sequence of semijoin reduction steps are performed, where each semijoin reduction step either switches one tuple list, or reduces all tuple lists at one relation. Virtual connector pairs are inserted into the tuple lists, and then all tuple lists are centralized at a common host. The join results are assembled at the common host, and negative row IDs are substituted. From the join result, the query result is retrieved by projecting to the requested attributes.

Abstract: Systems and methods for using optimization techniques to construct a nearly optimal execution plan for an outer join query are disclosed. A query graph of the outer join query is constructed, by computing for each node the set of nodes influencing it, for each target node the set of its needed reducers, and predetermining the effects of all admissible moves in all possible sequences. The directed graph of all admissible move sequences is formed. An optimization process includes dynamically generating good estimations for the target distance of a search state. Some heuristics are disclosed for providing start solutions for the optimization process.

Abstract: A document classification module may include a classification module that enables a user to classify documents using a combination of example-based classification (EBC) and query-based classification (QBC) methods. The user may also enter keywords with positive, negative, or null weights to fine tune the results of the classification process.