File and move data to shrink datafiles
A system, method, and computer-readable medium for consolidating all the currently used areas to the beginning of the datafile by performing a datafile reorganization operation. With this consolidation, more space can be recovered from the datafile. More specifically, with the consolidation, because each used area can contain extents related to several different segments, locating all the segments that have extents in a used area and relocate these segments to lower addresses in the datafile can be challenging.
1. A computer-implementable method, comprising:
locating segments that have extents in a used area of a datafile, the datafile comprising a datafile header portion, one or more datafile used area portions, one or more datafile unused but previously used area portion, and a datafile formatted portion, each segment containing a plurality of extents spread across non-contiguous areas of at least one datafile; and
relocating the segments that have extents in a used area to lower addresses in the datafile, the relocating the segments consolidating all unused extents within the datafile, for each segment to be relocated, the relocating the segments comprising:
creating a copy of the segment;
while creating the copy of the segment, identifying any changes made to the segment;
performing the changes to the copy of the segment;
swapping the segment with the copy of the segment; and
deleting the segment to release one or more extents at a higher address in the datafile.
2. The method of claim 1 , wherein:
all the extents in the used area are moved while a logical object of the datafile is being used, without affecting the applications using the logical objects.
3. The method of claim 1 , wherein the relocating further comprises:
copying the identified segments such that extents with corresponding data are created at lower addresses in the datafile.
4. The method of claim 3 , wherein:
after the copying is complete, the original segments are deleted so as to release locations corresponding to original extents at higher addresses in the datafile.
5. The method of claim 1 , wherein the locating further comprises:
identifying segments that own all used extents.
6. The method of claim 5 , wherein:
identifying segments that own used extents also identifies unused extents, including extents which were previously used and are above a location of a last used extent, extents which were previously used and are within a location of a last used extent and those that were unused.
7. The method of claim 1 , wherein swapping the segment with the copy of the segment comprises:
removing the segment from a storage location; and
saving the copy of the segment to the storage location.
8. The method of claim 1 , wherein identifying any changes made to the segment comprises identifying at least one of: an addition to, a deletion of at least a portion of, or a modification to the segment.
9. A system comprising:
a processor;
a data bus coupled to the processor; and
a non-transitory, computer-readable storage medium embodying computer program code, the non-transitory, computer-readable storage medium being coupled to the data bus, the computer program code interacting with a plurality of computer operations and comprising instructions executable by the processor to cause a system to perform operations comprising:
locating segments that have extents in a used area of the a datafile, the datafile comprising a datafile header portion, one or more datafile datafile used area portions, one or more datafile datafile unused but previously used area portion and a datafile formatted portion, each segment containing a plurality of extents spread across non-contiguous areas of at least one datafile; and
relocating the segments that have extents in a used area to lower addresses in the datafile, the relocating the segments consolidating all unused extents within the datafile, for each segment to be relocated, the relocating the segments comprising:
creating a copy of the segment;
while creating the copy of the segment, identifying any changes made to the segment;
performing the changes to the copy of the segment;
swapping the segment with the copy of the segment; and
deleting the segment to release one or more extents at a higher address in the datafile.
10. The system of claim 9 , wherein:
all the extents in the used area are moved while a logical object of the datafile is being used, without affecting the applications using the logical objects.
11. The system of claim 9 , wherein the relocating further comprises:
copying the identified segments such that extents with corresponding data are created at lower addresses in the datafile.
12. The system of claim 11 , wherein:
after the copying is complete, the original segments are deleted so as to release locations corresponding to original extents at higher addresses in the datafile.
13. The system of claim 9 , wherein the locating further comprises:
identifying segments that own all used extents.
14. The system of claim 13 , wherein:
identifying segments that own used extents also identifies unused extents, including extents which were previously used and are above a location of a last used extent, extents which were previously used and are within a location of a last used extent and those that were unused.
15. A non-transitory, computer-readable storage medium embodying computer program code, the computer program code comprising computer executable instructions that, when executed by a processor, cause a system to perform operations comprising:
locating segments that have extents in a used area of a datafile, the datafile comprising a datafile header portion, one or more datafile datafile used area portions, one or more datafile datafile unused but previously used area portion and a datafile formatted portion, each segment containing a plurality of extents spread across non-contiguous areas of at least one datafile; and
relocating the segments that have extents in a used area to lower addresses in the datafile, the relocating the segments consolidating all unused extents within the datafile, for each segment to be relocated, the relocating the segments comprising:
creating a copy of the segment;
while creating the copy of the segment, identifying any changes made to the segment;
performing the changes to the copy of the segment;
swapping the segment with the copy of the segment; and
deleting the segment to release one or more extents at a higher address in the datafile.
16. The non-transitory, computer-readable storage medium of claim 15 , wherein:
all the extents in the used area are moved while a logical object of the datafile is being used, without affecting the applications using the logical objects.
17. The non-transitory, computer-readable storage medium of claim 15 , wherein the relocating further comprises:
copying the identified segments such that extents with corresponding data are created at lower addresses in the datafile.
18. The non-transitory, computer-readable storage medium of claim 17 , wherein:
after the copying is complete, the original segments are deleted so as to release locations corresponding to original extents at higher addresses in the datafile.
19. The non-transitory, computer-readable storage medium of claim 15 , wherein the locating further comprises:
identifying segments that own all used extents.
20. The non-transitory, computer-readable storage medium of claim 19 , wherein:
identifying segments that own used extents also identifies unused extents, including extents which were previously used and are above a location of a last used extent, extents which were previously used and are within a location of a last used extent and those that were unused.