Methods and apparatus related to completion of large objects within a DB2 database environment
View Patent ↗In one general aspect, an apparatus can include a completion identifier configured to identify, for completion processing, a large object (LOB) deleted from an auxiliary table within a DB2 database environment based on a space map record associated with the large object where the auxiliary table functions as an auxiliary space to a base table. The apparatus can also include a completion analyzer configured to identify a resource where an image of the large object is stored at a time before the deletion of the large object from the auxiliary table.
1. An apparatus, comprising:
a memory; and
a processor operably coupled to the memory and configured to cause the apparatus to include:
a completion identifier configured to identify, for completion processing, a large object (LOB) deleted from an auxiliary table within a relational database management system environment based on a space map record associated with the large object, the auxiliary table functioning as an auxiliary space to a base table; and
a completion analyzer configured to identify a resource where an image of the large object is stored at a time before the deletion of the large object from the auxiliary table, wherein the resource is a backup of the auxiliary table stored at a time before the deletion of the large object.
2. The apparatus of claim 1 , wherein the resource is a backup of the auxiliary table and the image of the large object is a first image of the large object, and the completion analyzer is configured to identify a log including data related to a modification of the first image of the large object,
the apparatus further comprising:
a completion execution module configured to produce a second image of the large object based on the first image of the large object and based on the log.
3. The apparatus of claim 1 , wherein the large object is a first large object, the completion identifier is configured to identify a second large object modified within the auxiliary table,
the completion analyzer is configured to identify the resource as including an image of the second large object before modification of the second large object within the auxiliary table.
4. The apparatus of claim 1 , further comprising:
a completion execution module configured to retrieve at least a portion of the image of the large object from the resource; and
a recovery module configured to receive a recovery instruction, and configured to restore the at least the portion of the image of the large object to the auxiliary table in response to the recovery instruction.
5. The apparatus of claim 1 , wherein the large object stored in the auxiliary table is referenced within a record from a plurality of records in a base table.
6. The apparatus of claim 1 , further comprising:
a completion execution module configured to retrieve at least a portion of the image of the large object from the resource, and configured to store the at least the portion of the image of the large object in an image repository outside of the relational database management system environment.
7. The apparatus of claim 1 , wherein the resource is at least one of a log file or an auxiliary table backup identified based on a relational database management system catalog storing information about data maintained within the relational database management system environment.
8. The apparatus of claim 1 , wherein an image of the large object in response to being deleted is unlogged.
9. The apparatus of claim 1 , wherein the auxiliary table is a large object tablespace within the relational database management system environment.
10. A non-transitory computer-readable storage medium storing instructions that when executed cause a processor to perform a process, the instructions comprising instructions to:
determine that a large object (LOB) stored, at a first time, in an auxiliary table to a base table within a relational database management system environment has changed, at a second time, based on a space map record referencing the large object stored in the auxiliary table;
designate the large object for completion processing in response to the determination;
identify, in response to the designation of the large object for completion processing, a storage location of an image of the large object within a resource of the relational database management system environment based on the space map record and based on a relational database management system catalog; and
retrieve, as a portion of the completion processing, the image of the large object prior to a change from the storage location of the resource.
11. The non-transitory computer-readable storage medium of claim 10 , wherein the storage location spans a plurality of pages being linked in a sequential order,
the instructions further comprising instructions to:
retrieve, as a portion of the completion processing, a copy of the image of the large object prior to the change from the storage location of the resource based on processing of each page from the plurality of pages in the sequential order.
12. The non-transitory computer-readable storage medium of claim 10 , wherein the resource is a backup of the auxiliary table,
the instructions further comprising instructions to:
identify a log associated with the backup of the auxiliary table and stored after the backup of the auxiliary table was stored;
retrieve, as a portion of the completion processing, the image of the large object prior to the change from the storage location of the resource; and
produce a modified version of the image of the large object based on the log.
13. The non-transitory computer-readable storage medium of claim 10 , wherein at least a portion of the storage location of the image of the large object within the resource corresponds with at least a portion of a storage location of an image of the large object available in the auxiliary table.
14. The non-transitory computer-readable storage medium of claim 10 , wherein the large object is a first large object and the storage location is a first storage location,
the instructions further comprising instructions to:
designate a second large object for completion processing;
determine that an image of the second large object is available on the resource; and
retrieve the image of the second large object starting at a second storage location of the resource.
15. The non-transitory computer-readable storage medium of claim 10 , wherein the large object is stored in a storage location at the first time, the storage location is identified as being available for writing in the space map record at the second time.
16. The non-transitory computer-readable storage medium of claim 10 , wherein the large object is a first large object,
the instructions further comprising instructions to:
designate a second large object for completion processing; and
determine that an image of the second large object is available on the resource based on a space map record referencing the second large object and based on the relational database management system catalog.
17. The non-transitory computer-readable storage medium of claim 10 , wherein the large object is a first large object, the instructions further comprise instructions to:
identify a second large object modified within the auxiliary table, and
identify the resource as including an image of the second large object before modification of the second large object within the auxiliary table.
18. A non-transitory computer-readable storage medium storing instructions that when executed cause a processor to perform a process, the instructions comprising instructions to:
designate, for completion processing, a plurality of large objects (LOB) associated with an auxiliary table to a base table within a relational database management system;
identify, in response to the designation of the plurality of large objects for completion processing, a first plurality of resources for completion processing of a first portion of the plurality of large objects;
identify, in response to the designation of the plurality of large objects for completion processing, a second plurality of resources for completion processing of a second portion of the plurality of large objects; and
identify a resource common to the first plurality of resources and the second plurality of resources.
19. The non-transitory computer-readable storage medium of claim 18 , further comprising instruction to:
retrieve, as a portion of the completion processing, at least a portion of an image of a first large object from the plurality of large objects and a second large object from the plurality of large objects from the resource common to the first plurality of resources and the second plurality of resources.
20. The non-transitory computer-readable storage medium of claim 18 , further comprising instruction to:
iteratively calculate a cost for performing the completion processing based on the first plurality of resources and the second plurality of resources.
21. The non-transitory computer-readable storage medium of claim 18 , further comprising instruction to:
exclude at least a portion of the first plurality of resources for analysis during completion processing based on overlap between the first plurality of resources and the second plurality of resources.
22. The non-transitory computer-readable storage medium of claim 18 , further comprising instruction to:
receive a request to retrieve an image of at least one large object from a plurality of images at a specified time, at least a portion of the first plurality of resources is identified based on the specified time.