Oracle International Corporation

Vivekanandhan Raja

Amit Ganesh

Sanket Hase

Vineet Marwah

Tirthankar Lahiri

Sukhada Pendse

Atrayee Mullick

Vasudha Krishnaswamy

Shuang Su

Jesse Kamp

Bipul Sinha

Niloy Mukherjee

Kartik Kulkarni

Kenneth R Jacobs

Shasank Kisan Chavan

Yunrui Li

Jonathan D Klein

Mahesh Baburao Girkar

Allison Holloway

Teck Hua Lee

Michael J Gleeson

Krishna Kunchithapadam

Archna Kalra Johnson

Liang Guo

Joshua Gould

Juan R Loaiza

Thomas Baby

Kothanda Umamageswaran

Carol L Colrain

Todd Jeffery Little

Douglas N Surber

Jean De Lavarene

Kevin S Neel

Paul Parkinson

Neil MacNaughton

Stefan Heinrich Roesch

Nancy Reiko Ikeda

Sachin Vijaykumar Sonawane

Xiaoming He

J William Lee

Michael P Stewart

Mehul Dilip Bastawala

Muthu Olagappan

Michael John Skarpelos

Vipin Gokhale

Solmaz Kolahi

Jing Zheng

Maria Colgan

Shruti Gautam

Henry Chau

Aditi Gupta

Allison L Holloway

A database session in an active standby server on which an active standby database resides receives a DML statement. The session is suspended while the statement is redirected over a database link to a primary database on which the statement is executed. Information associated with execution of the statement is communicated to the session in the active standby server. Redo records describing changes to the contents of the primary database are applied to the active standby database and control is returned to the session. Prior to commitment of a transaction including the statement, a query directed to data to which the statement was directed is received at the active standby server from a client and executed on the active standby database absent use of a database link based on whether information associated with a database session associated with the client matches the information associated with execution of the statement.

Method and system for supporting data consistency on an active standby database after DML redirection to a primary database

Techniques related to query execution against an in-memory standby database are disclosed. A first database includes PF data stored on persistent storage in a persistent format. The first database is accessible to a first database server that converts the PF data to a mirror format to produce MF data that is stored within volatile memory. The first database server receives, from a second database server, one or more change records indicating one or more transactions performed against a second database. The one or more change records are applied to the PF data, and a reference timestamp is advanced from a first to a second timestamp. The first database server invalidates any MF data that is changed by a subset of the one or more transactions that committed between the first and second timestamps.

Query execution against an in-memory standby database

Techniques are described that are performed by one or more database management system (DBMS) of the plurality of DBMS nodes comprising one or more database servers performing database operations on one or more databases of the DBMS nodes. The techniques describe receiving, at a QC node, a distributed query that specifying a database of a target DBMS node. Without requesting from the target DBMS node a current logical timestamp of the DBMS node, calculating a synchronization timestamp for the distributed query. In one embodiment, the calculation of the synchronization timestamp for the distributed query is based on a current logical timestamp of the QC node and one or more previous logical timestamps of the target DBMS node that were received prior to the receiving the distributed query. The QC node sends a request to the target DBMS node to execute an operation of the query at the target DBMS node based on the synchronization timestamp. The QC node may receive result set(s) from all the target DBMS nodes based on the synchronization timestamp, and aggregate the final result set to return to the client application.

Global consistency with recency in distributed database management systems

Techniques for activity tracking, data classification, and in-database archiving are described. Activity tracking refers to techniques that collect statistics related to user access patterns, such as the frequency or recency with which users access particular database elements. The statistics gathered through activity tracking can be supplied to data classification techniques to automatically classify the database elements or to assist users with manually classifying the database elements. Then, once the database elements have been classified, in-database archiving techniques can be employed to move database elements to different storage tiers based on the classifications. However, although the techniques related to activity tracking, data classification, and in-database archiving may be used together as described above; each technique may also be practiced separately.

Techniques for activity tracking, data classification, and in database archiving

Techniques are described herein for distributing distinct portions of a database object across volatile memories of selected nodes of a plurality of nodes in a clustered database system. The techniques involve storing a unit-to-service mapping that associates a unit (a database object or portion thereof) to one or more database services. The one or more database services are mapped to one or more nodes. The nodes to which a service is mapped may include nodes in disjoint database systems, so long as those database systems have access to a replica of the unit. The database object is treated as in-memory enabled by nodes that are associated with the service, and are treated as not in-memory enabled by nodes that are not associated with the service.

Flexible in-memory column store placement

Techniques are described for maintaining coherency of a portion of a database object mirrored in a particular node of a database. The techniques involve maintaining invalidation logs which identify transactions that have committed to a database. Based on the invalidation logs, the particular node generates invalid-row ID metadata which identifies, for each system change number, one or more rows that are not transactionally consistent with data stored in the database object as of said system change number.

Enhancing consistent read performance for in-memory databases

Techniques are described for maintaining coherency of a portion of a database object populated in the volatile memories of multiple nodes in a database cluster. The techniques involve maintaining a local invalidation bitmap for which identifies block-level invalidity data and item-level invalidity data. In response to detecting a patch-up triggering event, a particular node identifies, in the block-level invalidity data, blocks that have been marked as invalid. For each block that has been marked as invalid, the node identifies specific items that have changed and marks the items as invalid in the item-level invalidity data. The node then updates the block-level invalidity data to indicate that the blocks are no longer invalid.

Patch-up operations on invalidity data

A system and method for reducing communications overhead in a distributed transaction processing environment such as an XA environment. In accordance with an embodiment communication overhead is reduced in a transaction by deferring a transaction end communication. The deferred transaction end communication is determined from a subsequent XA transaction communication thereby reducing the number of networks calls required for each transaction and enhancing system performance.

System and method for reducing communications overhead in a distributed transactions environment by modifying implementation of the transaction end function

A minimum value (MV) is computed for start timestamps that each correspond to an uncommitted transaction. In an embodiment, the MV is computed for a pluggable database that is open on at least first and second instances of a database. The MV is computed for the first instance as of a first current timestamp (CT). The MV and the first CT are communicated to a second instance that has a second CT. If the first and second CTs are equal, the second instance store the MV. If the first CT is bigger, the second CT also becomes equal to the first CT. If the first CT is smaller, the MV is discarded, and the first CT becomes equal to the second CT. In an embodiment, if the MV remains unchanged for a predetermined time period, a start timestamp corresponding to the MV is advanced to a current or future timestamp.

Efficient determination of committed changes

Techniques are provided for maintaining data persistently in one format, but making that data available to a database server in more than one format. For example, one of the formats in which the data is made available for query processing is based on the on-disk format, while another of the formats in which the data is made available for query processing is independent of the on-disk format. Data that is in the format that is independent of the disk format may be maintained exclusively in volatile memory to reduce the overhead associated with keeping the data in sync with the on-disk format copies of the data.

Mechanism to run OLTP workload on in-memory database under memory pressure

Techniques are described for maintaining coherency of a portion of a database object populated in the volatile memories of multiple nodes in a database cluster. The techniques involve maintaining a local invalidation bitmap for chunks of data stored in memory in each particular node in the cluster by tracking locks granted by a lock manager. During a pre-loading operation, each given node requests a set of shared locks associated with the chunks of data to be store in the given node's memory. When a request to release one of these shared locks occurs, the in-memory copy of those data items may be invalidated in the node releasing its shared lock.

Maintaining cross-node coherence of an in-memory database object in a multi-node database cluster

Techniques for lifecycle state management and in-database archiving are described. Activity tracking refers to techniques that collect statistics related to user access patterns, such as the frequency or recency with which users access particular database elements. The statistics gathered through activity tracking can be supplied to data classification techniques to automatically classify the database elements or to assist users with manually classifying the database elements. Then, once the database elements have been classified, in-database archiving techniques can be employed to move database elements to different storage tiers based on the classifications. However, although the techniques related to activity tracking, data classification, and in-database archiving may be used together as described above; each technique may also be practiced separately.

Techniques for lifecycle state management and in-database archiving

Growing community of inventors

San Mateo, CA, United States of America

Vivekanandhan Raja