Abstract:
An exact cardinality query optimization system and method for optimizing a query having a plurality of expressions to obtain a cardinality-optimal query execution plan for the query. Embodiments of the system and method use various techniques to shorten the time necessary to obtain the cardinality-optimal query execution plan, which contains the query execution plan when all cardinalities are exact. Embodiments of the system and method include a covering queries technique that leverages query execution feedback to obtain an unordered subset of relevant expressions for the query, an early termination technique that bounds the cardinality to determine whether the processing can be terminate before each of the expressions are executed, and an expressions ordering technique that finds an ordering of expressions that yields the greatest reduction in time to obtain the cardinality-optimal query execution plan.
Abstract:
A set of documents is filtered for entity extraction. A list of entity strings is received. A set of token sets that covers the entity strings in the list is determined. An inverted index generated on a first set of documents is queried using the set of token sets to determine a set of document identifiers for a subset of the documents in the first set. A second set of documents identified by the set of document identifiers is retrieved from the first set of documents. The second set of documents is filtered to include one or more documents of the second set that each includes a match with at least one entity string of the list of entity strings. Entity recognition may be performed on the filtered second set of documents.
Abstract:
Selectivity estimates are produced that meet a desired confidence threshold. To determine the confidence level of a given selectivity estimate for a query expression, the query expression is evaluated on a sample tuples. A probability density function is derived based on the number of tuples in the sample that satisfy the query expression. The cumulative distribution for the probability density function is solved for the given threshold to determine a selectivity estimate at the given confidence value.
Abstract:
At least one implementation of database management technology, described herein, utilizes categorization of query results when querying a relational database in order to reduce information overload. To reduce information overload even further, another implementation, described herein, utilizes both categorization and ranking of query results when searching a relational database.
Abstract:
Example-driven creation of record matching queries. The disclosed architecture employs techniques that exploit the availability of positive (or matching) and negative (non-matching) examples to search through this space and suggest an initial record matching query. The record matching task is modeled as that of designing an operator tree obtained by composing a few primitive operators. This ensures that record matching programs be executable efficiently and scalably over large input relations. The architecture joins records across multiple (e.g., two) relations (e.g., R and S). The architecture exploits the monotonicity property of similarity functions for record matching in the relations, in that, any pair of matching records have a higher similarity value than non-matching record pairs on at least one similarity function.
Abstract:
A set similarity join system and method are provided. The system can be employed to facilitate data cleaning based on similarities through the identification of “close” tuples (e.g., records and/or rows). “Closeness” can be is evaluated using a similarity function(s) chosen to suit the domain and/or application. Thus, the system facilitates generic domain-independent data cleansing.The system can be employed with a foundational primitive, the set similarity join (SSJoin) operator, which can be used as a building block to implement a broad variety of notions of similarity (e.g., edit similarity, Jaccard similarity, generalized edit similarity, hamming distance, soundex, etc.) as well as similarity based on co-occurrences. The SSJoin operator can exploit the observation that set overlap can be used effectively to support a variety of similarity functions. The SSJoin operator compares values based on “sets” associated with (or explicitly constructed for) each one of them.
Abstract:
Aggregation queries are performed by first identifying outlier values, aggregating the outlier values, and sampling the remaining data after pruning the outlier values. The sampled data is extrapolated and added to the aggregated outlier values to provide an estimate for each aggregation query. Outlier values are identified by selecting values outside of a selected sliding window of data having the lowest variance. An index is created for the outlier values. The outlier data is removed from the window of data, and separately aggregated. The remaining data without the outliers is then sampled to provide a statistically relevant sample that is then aggregated and extrapolated to provide an estimate for the remaining data. This sampled estimate is combined with the outlier aggregate to form an estimate for the entire set of data.
Abstract:
A localized marketing system is disclosed that provides discount offers to users that match merchant criteria including proximity. Further, a system for actively probing populations of users with different parameters and monitoring responses can be employed to collect data for identifying the best discounts and deadlines to offer to users to achieve desired results.Another aspect of the disclosure pertains to web searches and more particularly toward influencing resultant content to increase relevancy. The resultant content can be influenced by reconfiguring a query and/or filtering results based on user location and/or context information (e.g., user characteristics/profile, prior interaction/usage temporal, current events, and third party state/context . . . ). Furthermore, the disclosure provides for query execution on at least a subset of designated web content, for example as specified by a user.
Abstract:
A method of estimating cardinality of a join of tables using multi-column density values and additionally using coarser density values of a subset of the multi-column density attributes. In one embodiment, the subset of attributes for the coarser densities is a prefix of the set of multi-column density attributes. A number of tuples from each table that participate in the join may be estimated using densities of the subsets. The cardinality of the join can be estimated using the multi-column density for each table and the estimated number of tuples that participate in the join from each table.
Abstract:
A database object summarization tool is provided that selects a subset of database objects subject to filtering constraints such as a partial order or optimization of some attribute. A dominance primitive filters out tuples that are dominated according to a partial order constraint by another tuple. A representation primitive selects a representative subset of tuples such than an optimization criteria is met.