Abstract: Techniques are provided for processing a CREATE INDEX statement that avoids one or more locks on the underlying table. The processing of such a statement may be divided into a build phase and a cooperation phase. During the build phase, a journal table is created and published. A snapshot of the table is obtained after the last DML transaction (that was pending at the time the journal table was published) commits. The index is built based on the state of the table as of the snapshot. Any changes to the table while the index is built are recorded in the journal table. During the cooperation phase, the index is partially published. A subsequent DML statement determines whether any changes in the journal table affect the same data as the subsequent DML statement. If so, then those changes are applied to the index followed by the subsequent DML statement.

Abstract: A computer modifies data inside a database large object (LOB) of unknown structure without modifying other data in the remainder of the LOB. Insertion of new data at a specified location in the LOB does not require movement of existing data in the LOB. Instead, the computer is programmed to insert new data at a physical end of the LOB, and modify metadata based on the specified location. Similarly, deletion of existing data from a specified location in the LOB is performed without movement of other data in the LOB, by updating the metadata. The computer uses the metadata when reading from the LOB, so that the new data is automatically read whenever the specified location is accessed. The computer may optionally output a handle that is static, relative to other insertions and deletions, to identify specific data within the LOB, for use in building indexes on the LOB.

Abstract: Performing an operation directly on data stored in a database table provides for avoiding generation and processing of SQL statements. A Data Layer interface, comprising a set of APIs, allows internal database server components to call directly to the Data Layer for making fast row changes to a table. According to an embodiment, before making any row change to a table through this Data Layer interface, a shared state data structure is created to hold the metadata about the table. A single shared state can be used for all DML changes to a particular table regardless of what columns are updated or inserted during each DML operation. When a process needs to change a row, the process uses a mutable state based on the shared state of the table.

Abstract: A method of processing data from a file includes obtaining a first portion of the file, creating a first compression unit by compressing at least the first portion of the file, obtaining a second portion of the file, creating a second compression unit by compressing at least the second portion of the file, and storing the first and second compression unit such that each of the first and the second compression units can be individually accessed. A method of processing data from a file includes receiving a request to access a portion of the file, determining one or more sub-units that include compressed data associated with the portion of the file, de-compressing the compressed data in the one or more sub-units to obtain de-compressed data, and transmitting the de-compressed data in response to the request.

Abstract: A method of processing data from a file includes obtaining a first portion of the file, encrypting the first portion of the file to create a first encrypted portion, obtaining a second portion of the file, encrypting the second portion of the file to create a second encrypted portion, and storing the first and second encrypted portions such that each of the first and the second encrypted portions can be individually accessed. A method of processing data from a file includes receiving a request to access a first portion of the file, wherein data in the first portion of the file is encrypted, and data in a second portion of the file is encrypted, and decrypting the data in the first portion, and not the data in the second portion.

Abstract: Methods and systems for automatically tuning the undo retention in a database system are disclosed. The undo tablespace may be of a fixed size or may be set to be automatically extended. If the undo tablespace is of a fixed size, the undo retention is set to a “best possible” undo retention, which is calculated based on statistical data stored in the system. If the undo tablespace is configured to be automatically extensible, the undo retention may be set to be greater than the duration of the longest running query in the system. The duration of the longest running query may be calculated in a distributed process in which each instance broadcasts information about its longest running query to other instances.