Patent application number | Description | Published |
20090024568 | DATA SKEW INSENSITIVE PARALLEL JOIN SCHEME - A method for creating a joined data set from a join input data set is disclosed. The method starts by categorizing the join input data set into a high-skew data set and a low-skew data set. The low-skew data set is distributed to the plurality of CPUs using a first distribution method. The high-skew data set is distributed to the plurality of CPUs using a second distribution method. The plurality of CPUs process the high-skew data set and the low-skew data set to create the joined data set. | 01-22-2009 |
20110029508 | SELECTIVITY-BASED OPTIMIZED-QUERY-PLAN CACHING - Embodiments of the present invention partition optimized query plans into equivalence groups, each comprising one or more equivalence classes. Each equivalence group corresponds to a particular compiled, normalized, and parameterized query plan prior to optimization. Each equivalence class within an equivalence group corresponds to a different query plan corresponding to the particular compiled, normalized, and parameterized query plan represented by the equivalence group that has been optimized with respect to the selectivity of one or more predicate clauses of the query that is compiled to produce the particular compiled, normalized, and parameterized query plan. Optimized query plans are cached according to their respective equivalence groups and equivalence classes. When a query, similar to a query already compiled, optimized, and cached, is subsequently received and compiled, a selectivity for a predicate of the compiled query is computed, allowing the database management system to retrieve a cached query plan optimized for a similar query with similar selectivity. | 02-03-2011 |
20120117055 | Data Skew Insensitive Parallel Join Scheme - A method for creating a joined data set from a join input data set is disclosed. The method starts by categorizing the join input data set into a high-skew data set and a low-skew data set. The low-skew data set is distributed to the plurality of CPUs using a first distribution method. The high-skew data set is distributed to the plurality of CPUs using a second distribution method. The plurality of CPUs process the high-skew data set and the low-skew data set to create the joined data set. | 05-10-2012 |
20120179669 | SYSTEMS AND METHODS FOR SEARCHING A SEARCH SPACE OF A QUERY - One example discloses a database management system that can comprise a memory for storing computer executable instructions and a processing unit for accessing the memory and executing the computer executable instructions. The computer executable instructions can comprise a compiler to amortize the execution resource cost of searching a search space corresponding to a received query over a plurality of searches. | 07-12-2012 |
20130232133 | SYSTEMS AND METHODS FOR PERFORMING A NESTED JOIN OPERATION - Systems and methods are provided for performing a nested join operation. Partitioning key values are computed for an outer data source using a partitioning key function used to partition an inner table. A join process is established for each of a plurality of partitions of the inner table (at | 09-05-2013 |
20140149433 | Estimating Unique Entry Counts Using a Counting Bloom Filter - A method of estimating a number of unique entry counts of an attribute in a database comprises, with a processor: identifying a sample of entries from an attribute database, determining frequencies of a number of input observations of the sample of entries, determining a number of high frequency values of the sample of entries, and estimating a number of unique entry counts of an attribute within the attribute database using a counting Bloom filter and based on the frequencies of the input observations and the high frequency values. | 05-29-2014 |
20140330768 | INCREMENTALLY UPDATED SAMPLE TABLES - An example apparatus may include a processor and a memory device including computer program code. The memory device and the computer program code may be for, with the processor, causing the apparatus to delete, in a sample table, rows corresponding to a predicate, wherein rows in the sample table are representative of a random sample of rows in a base table of a database; generate sample rows representative of a random sample of rows in the base table corresponding to the predicate; and add the sample rows to the sample table to generate an incrementally updated sample table. | 11-06-2014 |
20160110417 | Incrementally Updating Statistics - Incrementally updating statistics includes sampling rows from a database column in a database to generate a first sample, sampling a subset of modified rows from the database column after generating the first sample to generate a second sample, determining whether distribution changes occurred to the database column based on the first and second samples, and updating a database statistic about the database column in response to determining that a distribution change exists. | 04-21-2016 |