摘要:
A method and an apparatus that improves virtual memory management. The proposed method and apparatus provides an application with an efficient channel for communicating information about future behavior of an application with respect to the use of memory and other resources to the OS, a paging daemon, and other system software. The state of hint bits, which are integrated into page table entries and TLB entries and are used for communicating information to the OS, can be changed explicitly with a special instruction or implicitly as a result of referencing the associated page. The latter is useful for canceling hints. The method and apparatus enables memory allocators, garbage collectors, and compilers (such as those used by the Java platform) to use a page-aligned heap and a page-aligned stack to assist the OS in effective management of memory resources. This mechanism can also be used in other system software.
摘要:
The invention teaches how to reduce the traffic associated with handling cache lines containing useless data (i.e. cache lines corresponding to pages that have been invalidated). The invention makes it possible to evict such cache lines earlier, to avoid write backs of useless data from such cache lines to main memory, and to avoid transmitting useless data from such cache lines to the requesting remote coherence controller in a multiprocessor system. The present invention describes a mechanism for invalidating cache lines containing useless data transparently and without programmer's involvement. For efficiency, the content of a cache line containing useless data is invalidated only when the line is referenced or is about to be allocated for some new data.
摘要:
Techniques for database table look-up are provided. The techniques include storing one or more column attributes of a database table in a data structure, wherein the data structure also comprises a record identification (RID) column of a table, one or more predicate columns corresponding to the RID column, and a sequence number column that is associated with one or more updated records, generating a key using one or more portions from one or more of the one or more predicate columns, using the key to partition the data structure, wherein partitioning the data structure comprises partitioning the one or more predicate columns for evaluation, and evaluating the one or more predicate columns against the data structure for each matching predicate column-data structure partition.
摘要:
An apparatus and method for efficiently performing a query sort on a data set with duplicate key values is disclosed. The method includes identifying unique key values for a key in a data set after determining that a number of duplicate key values for the key exceed a predefined threshold. The method also includes recording an association of each unique key value with a record in the data set and sorting unique key values. The method further includes storing the unique key values in a sorted order, wherein each unique key value is associated with an appropriate record in the data set.
摘要:
Techniques for storage allocation of a data record are provided. The techniques include attempting to identify a first location for storing a data record, wherein the data record comprises one or more data record attributes, if the first location is identified, selecting the first location for storing the data record, and if the first location is not identified, identifying a second location for storing the data record using a cost penalty function and selecting the second location for storing the data record based on the cost penalty function.
摘要:
Techniques for database table look-up are provided. The techniques include storing one or more column attributes of a database table in a data structure, wherein the data structure also comprises a record identification (RID) column of a table, one or more predicate columns corresponding to the RID column, and a sequence number column that is associated with one or more updated records, generating a key using one or more portions from one or more of the one or more predicate columns, using the key to partition the data structure, wherein partitioning the data structure comprises partitioning the one or more predicate columns for evaluation, and evaluating the one or more predicate columns against the data structure for each matching predicate column-data structure partition.
摘要:
An apparatus and method for efficiently performing a query sort on a data set with duplicate key values is disclosed. The method includes identifying unique key values for a key in a data set after determining that a number of duplicate key values for the key exceed a predefined threshold. The method also includes recording an association of each unique key value with a record in the data set and sorting unique key values. The method further includes storing the unique key values in a sorted order, wherein each unique key value is associated with an appropriate record in the data set.
摘要:
A sequence of one or more input objects are sorted by identifying a property that is exhibited by a sequence of one or more input objects, determining whether each input object from the sequence of one or more input objects exhibits the property, storing each of the one or more input objects into a buffer, wherein an input object is stored in a first buffer if it exhibits the property and an input object is stored in a second buffer if it does not exhibit the property, sorting each of the one or more input objects in each buffer, and merging the one or more input objects in each buffer into a sequence of one or more input objects.
摘要:
Techniques for storage allocation of a data record are provided. The techniques include attempting to identify a first location for storing a data record, wherein the data record comprises one or more data record attributes, if the first location is identified, selecting the first location for storing the data record, and if the first location is not identified, identifying a second location for storing the data record using a cost penalty function and selecting the second location for storing the data record based on the cost penalty function.
摘要:
Techniques for sorting a sequence of one or more input objects are provided. The techniques include identifying a property that is exhibited by a sequence of one or more input objects, determining whether each input object from the sequence of one or more input objects exhibits the property, storing each of the one or more input objects into a buffer, wherein an input object is stored in a first buffer if it exhibits the property and an input object is stored in a second buffer if it does not exhibit the property, sorting each of the one or more input objects in each buffer, and merging the one or more input objects in each buffer into a sequence of one or more input objects.