Abstract: The present disclosure relates to example table connection methods, devices, and systems. In one example method, data that is sent by a coordinator node and that is in a first target column in a first data table is stored by a data node in a local memory. The data node receives a table connection request. When first data in the first target column is the same as second data in a second target column, the data node connects data in a row in which the first data is located to data in a row in which the second data is located. The data node sends a connection result to the coordinator node.

Abstract: Embodiments of the present invention disclose a storage method and a query method for a database, and an apparatus, and relate to the field of computer technologies. A specific solution is: receiving a query request, where the query request is used to query data that is in a database and that meets a query condition; determining a data query range corresponding to the query condition, and determining a matched index item from multiple index items, where a value range indicated by an index key in the matched index item includes the data query range; and reading the data from a storage unit to which an index value in the matched index item points.

Abstract: A transaction recovery method in a database system and a database management system, where the database management system determines a transaction in the database system, which is not committed, and has performed an update operation on data in the database system, obtains, from an update operation log recording the update operation, a physical address of an old value of the data in the storage device, where the old value is a value of the data before the update operation, replaces a physical address of a new value of the data with the physical address of the old value, and sets the physical address of the new value to invalid such that a logical address of the data points to the physical address of the old value, where the new value is a value of the data after the update operation.

Abstract: The present disclosure relates to example table connection methods, devices, and systems. In one example method, data that is sent by a coordinator node and that is in a first target column in a first data table is stored by a data node in a local memory. The data node receives a table connection request. When first data in the first target column is the same as second data in a second target column, the data node connects data in a row in which the first data is located to data in a row in which the second data is located. The data node sends a connection result to the coordinator node.

Abstract: A read cache management method and apparatus based on a solid state drive, and the method includes: determining whether a read request hits a first queue and a second queue (S101); if both the first queue and the second queue are missed, selecting and deleting an eliminated data block from the first queue (S102); if the eliminated data block is in a stored state, inserting the eliminated data block into the second queue (S103); and determining a target data block in a lower-level storage medium, and inserting the target data block into the first queue, (S104). According to the foregoing read cache management method and apparatus based on the solid state drive, a hit ratio of the solid state drive can be increased, a data write count of the solid state drive can be reduced, and service life of the solid state drive can be extended.

Abstract: The present embodiments provide a cache data determining method and apparatus, and pertain to the field of computer technologies. The method includes: acquiring a data identifier of read cache miss data; selecting, based on the acquired data identifier, a data identifier of to-be-determined data; recording data identifiers by groups; collecting statistics on quantities of occurrence times, in each group, of the data identifiers; and selecting target to-be-determined data according to the quantities of occurrence times, and determining the target to-be-determined data as cache miss data to be written into a cache memory. Data identifiers are recorded by groups, and after statistics on quantities of occurrence times, in each group, of the data identifiers is collected, target to-be-determined data is selected according to the quantities of occurrence times, and the target to-be-determined data is determined as cache miss data to be written into a cache memory.

Abstract: A read cache management method and apparatus based on a solid state drive, and the method includes: determining whether a read request hits a first queue and a second queue (S101); if both the first queue and the second queue are missed, selecting and deleting an eliminated data block from the first queue (S102); if the eliminated data block is in a stored state, inserting the eliminated data block into the second queue (S103); and determining a target data block in a lower-level storage medium, and inserting the target data block into the first queue, (S104). According to the foregoing read cache management method and apparatus based on the solid state drive, a hit ratio of the solid state drive can be increased, a data write count of the solid state drive can be reduced, and service life of the solid state drive can be extended.

Abstract: A generation method, a query method, and an apparatus of a two-dimensional filter are provided. In this solution, a two-dimensional filter includes a two-dimensional matrix, where the two-dimensional matrix may be linked to multiple key value element groups, and therefore flexibility of the filter is improved. Further, when it is queried whether a key value element is a key value element included in multiple key value element groups, it only needs to perform a query based on the two-dimensional filter, and it does not need to generate a Bloom filter corresponding to each key value element group. In addition, when it is queried whether a key value element is a key value element included in multiple key value element groups, it does not need to perform queries one by one based on each of multiple Bloom filters. Therefore, a problem of low query efficiency currently is further resolved.

Abstract: A data processing method and apparatus, which relate to the computer field and are capable of effectively improving scalability of a database system. The data processing method includes: receiving source code of an external routine, where the source code of the external routine is compiled by using an advanced programming language; compiling the source code to obtain intermediate code, where the intermediate code is a byte stream identifiable to a virtual machine on any operating platform; converting, according to an instruction set on the operating platform, the intermediate code into machine code capable of running on the operating platform; and storing the machine code to a database. The data processing method and apparatus provided by the embodiments of the present invention are used to process data.

Abstract: A data processing method and apparatus, which relate to the computer field and are capable of effectively improving scalability of a database system. The data processing method includes: receiving source code of an external routine, where the source code of the external routine is compiled by using an advanced programming language; compiling the source code to obtain intermediate code, where the intermediate code is a byte stream identifiable to a virtual machine on any operating platform; converting, according to an instruction set on the operating platform, the intermediate code into machine code capable of running on the operating platform; and storing the machine code to a database. The data processing method and apparatus provided by the embodiments of the present invention are used to process data.