Abstract: A method for reliable data synchronization within a network is disclosed. The producer system stories data in a persistent data store and produces one or more data updates. The producer system simultaneously transmits the data updates to a consumer system and initiating storage of the data updates at the producer system. When storage of the data updates at the producer system is complete, the producer system transmits a first acknowledgment to the consumer system. The producer system determines whether a second acknowledgment has been received from the consumer system, wherein the second acknowledgment indicates that the consumer system has successfully stored the data updates at the consumer system. In accordance with a determination that the second acknowledgment has been received from the consumer system, the producer system changes the temporary status of the data updates stored at the producer system to a permanent status.

Abstract: Techniques of implementing partition level operations with concurrent activities are disclosed. A first operation can be performed on a first partition of a table of data. The first partition can be one of a plurality of partitions of the table, where each partition has a plurality of rows. A first partition level lock can be applied to the first partition for a period in which the first operation is being performed on the first partition, thereby preventing any operation other than the first operation from being performed on the first partition during the period the first partition level lock is being applied to the first partition. A second operation can be performed on a second partition of the table at a point in time during which the first operation is being performed on the first partition.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: An original query execution plan of a database query is received. The original query execution plan represents a tree of operators. Source code for the original query execution plan is generated by a single traversal of the tree of operators. The generated source code is compiled into native machine code. The native machine code represents a simplified native access plan (SNAP).

Abstract: Disclosed herein are system, method, and computer program product embodiments for deferring or eliminating a need to decompress database data. An embodiment operates by decompressing a column of a database. The column may be represented by a predicate of a query. A row of the database may be determined to satisfy the predicate based on decompressed information from the column. Decompression of an additional column of the row may be deferred during execution the query until the row is determined to satisfy the predicate. The additional column may satisfy the query.

Abstract: A system for managing database logging, the comprises a processor; and a user task executing in a database server process and executable by the processor, the user task to: receive in a database management system on a database server, a command to manipulate a portion of a database managed by the database management system; obtain a lock on the portion of the database; create a first log record in a first private log cache associated with the user task, the first log record recording a data manipulation to the portion of the database; enqueue the first log record to a queue; and release the lock on the portion of the database after copying the first log record to the queue.

Abstract: A system and method for processing a database query is described. In response to detection that a database query involves a star or snowflake join operation, a join operator in a preliminary query plan can be split into a build operator and a probe operator. The probe operator can be placed in a final query plan in the same place as the join operator in the preliminary query plan, while the build operator can be placed beneath the probe operator in the final query plan, between an exchange operator and the exchange operator's child from the preliminary query plan.

Abstract: Embodiments include a method, apparatus and computer program product for providing access to a database data source during database maintenance. The method includes initiating maintenance of the database data source and managing the database maintenance to allow concurrent access to the database data source.

Abstract: Techniques of implementing partition level operations with concurrent activities are disclosed. A first operation can be performed on a first partition of a table of data. The first partition can be one of a plurality of partitions of the table, where each partition has a plurality of rows. A first partition level lock can be applied to the first partition for a period in which the first operation is being performed on the first partition, thereby preventing any operation other than the first operation from being performed on the first partition during the period the first partition level lock is being applied to the first partition. A second operation can be performed on a second partition of the table at a point in time during which the first operation is being performed on the first partition.

Abstract: Guaranteed message sequencing between a first and second database is described. An example method includes maintaining first state information associated with the first database at the first database, where second state information associated with the first database is maintained at the second database. The client sends, to the second database, a message describing changed rows between the first database and the second database since a last synchronization and the first state information. The client subsequently receives, from the second database, status of the last synchronization, where the status is determined by the second database based on the first state information and the second state information.

Abstract: Increasing the efficiency of performing queries on databases by eliminating partitions during a database query. The database query configured to access a database table having one or more columns and one or more rows, the database query including a condition on a specified basis column. The database table being partitioned on the basis of the specified column, the specified column having one or more distinct values and the partitioning including mapping, by the at least one programmable processor, individual ones of the one or more distinct values to individual partitions causing each row in the table to be mapped to a specific partition. Candidate partitions and guaranteed partitions can be identified. The database query can be applied only to candidate partitions. All rows which satisfy the database query and all the rows of the guaranteed partition can be forward for processing.

Abstract: Disclosed herein are methods for retrieving data from a database. An embodiment operates searching for a key in a first index. The method determines that the searching will require a storage access request and issues the storage access request. The method continues searching for the key in a second index.

Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a native access plan for semi join operators. An embodiment operates by generating a plurality of variables based upon the positions of a plurality of operators in a compiled query plan, opening and traversing tables as the query plan is executed, and closing those tables based on the rows queried and the plurality of variables.

Abstract: Disclosed in some examples is a method of database replication, the method including at a Relational Database Management System (RDMS), determining a first replication mode; identifying a triggering event; determining that the triggering event indicates a change in the first replication mode; responsive to determining that the triggering event indicates a change in the first replication mode, determining a second replication mode, the second replication mode being a different replication mode than the first replication mode; identifying a database change made by one or more database tasks; and replicating the database change to an external replication component according to the second replication mode.

Abstract: A method may include accepting a database query including an operator requesting two or more incoming tuple streams be combined into a result tuple stream. At least one data value in the incoming tuple streams may be represented by an enumeration value. The method may include generating a query execution plan for the database query. The query execution plan may include encoding the enumeration value and a corresponding source identifier into a composite union enumeration. The source identifier may identify which of the two or more tuple streams corresponds to the enumeration value. The method may further include executing the database query according to the query execution plan to obtain the data value and providing the data value in response to the database query.

Abstract: In an example embodiment, one or more pages from a database are stored in a page cache stored in a shared memory, the one or more pages stored in a packed format. One or more rows from the database are stored in a row cache stored in the shared memory, the one or more rows stored in an unpacked format. A request for a row of the database is received. Then, the row cache is searched for the row. In response to a determination that the row cannot be found in the row cache, the page cache is searched for the row. Finally, the row is returned.

Abstract: An operator tree is formed for a data processing plan, the operator tree containing a plurality of interconnected nodes and including a grouping of two or more duplicative portions, each of the two or more duplicative portions having identical nodes and structure such that when the operator tree is executed, operators executed in a first duplicative portion using a first thread perform same functions use different data than operators in a second duplicative portion using a second thread. One or more operators in the first portion and one or more operators in the second portion to be synchronized with each other are identified. A synchronization point is created for the identified operators in the first thread and one or more subsequent threads, wherein the synchronization point receives information from each of the identified operators to build an artifact to deliver to one or more operators that depend on the artifact.

Abstract: Disclosed herein are system, method, and computer program product embodiments for generating a native access plan from a query execution plan for dynamic entity calling. An embodiment operates by receiving the query execution plan comprising at least one call to an entity, the entity being implemented by a plurality of classes, and generating source code of a native access plan that implements the query execution plan. The source code of the native access plan includes instructions to translate a run-time call to the entity to a call to a corresponding implementation of the entity based on an identifier of the called implementation of the entity.

Abstract: In an example embodiment performance is optimized in a complex event stream (CEP) system. Information about a plurality of CEP threads is obtained. Then nearness among the plurality of CEP threads is determined, wherein nearness between a first and a second CEP thread indicates how much interaction is expected to occur between the first and second CEP thread. Based on the determined nearness, the plurality of CEP threads are organized into a plurality of CEP thread groups. Then, each of the plurality of CEP thread groups are assigned to a different processing node, with each processing node having one or more processors and a memory.

Abstract: A database query may include an operator requesting two or more incoming tuple streams be combined into a result tuple stream. Generating a query execution plan may include constructing an equivalence union enumeration lookup table for a result domain of an element within the result tuple stream by taking a set union of incoming tuple domains, wherein each distinct value within that result domain is assigned an enumeration value. Generating the query execution plan may include constructing a secondary enumeration for each incoming tuple stream, wherein each secondary enumeration maps enumerated values within the incoming tuple stream into secondary ordinal values that correspond to equivalence union enumeration values.