Purging storage partitions of databases
Examples relate to purging storage partitions of a database. The examples disclosed herein identify a first partition of a database to be purged and identify a data entry in the first storage partition, where the data entry is to be copied. Examples herein copy an updated version of the data entry to a future storage partition of the database and purge the first storage partition. A dummy data entry is created in a second storage partition of the database, where the dummy data entry identifies the future storage partition.
1. A method comprising:
identifying, by a processor, a first table partition to be purged, wherein the first table partition is one of a plurality of table partitions of a database table, and wherein the plurality of table partitions are separated according to time ranges;
identifying, by the processor, a database entry in the first table partition, wherein the identified database entry is to be copied to a different table partition of the database table;
copying, by the processor, an updated version of the identified database entry to a future table partition of the database table;
purging, by the processor, the first table partition; and
in response to a purge of the first table partition, creating, by the processor, a dummy database entry in a second table partition of the database table, wherein the dummy database entry stores an identifier for the future table partition, and wherein the second table partition is a second oldest table partition of the database table.
2. The method of claim 1 , wherein identifying the database entry in the first table partition to be copied comprises identifying a database entry in the database table that has a latest version stored in the first table partition.
3. The method of claim 1 , wherein identifying the first table partition to be purged comprises identifying an oldest table partition of the database table.
4. The method of claim 1 , wherein the second table partition becomes an oldest table partition of the database table after the first table partition is purged.
5. The method of claim 1 , wherein the future table partition is an empty table partition before the identified database entry is copied to the future table partition.
6. The method of claim 1 , further comprising updating a cache to include the updated version of the identified database entry, wherein the cache stores latest versions of each database entry in the database table.
7. The method of claim 6 , wherein updating the cache comprises querying the database table to locate the dummy database entry and updating the cache with database entries stored in the future table partition.
8. The method of claim 1 , wherein the database table is a columnar database table.
9. The method of claim 1 , wherein the database table comprises a log-structured merge-tree data structure.
10. The method of claim 1 , comprising copying updated versions of a plurality of database entries identified in the first table partition to a plurality of future table partitions of the database table, and wherein the dummy database entry stores identifiers for the plurality of future table partitions of the database table.
11. A non-transitory machine-readable storage medium encoded with instructions executable by a processor of a computing device to:
identify a first table partition of a database table to be purged by identifying an oldest table partition of the database table, wherein the first table partition is one of a plurality of table partitions of the database table, and wherein the plurality of table partitions are separated according to time ranges;
identify a database entry in the first table partition, wherein a latest version of the identified database entry in the database table is stored in the first table partition, and wherein the identified database entry is to be copied to another table partition;
copy an updated version of the database entry to a future table partition of the database table;
purge the first table partition; and
create a dummy database entry in a second table partition of the database table, wherein the dummy database entry stores an identifier for the future table partition, and wherein the second table partition is a second oldest table partition of the database table and becomes the oldest table partition of the database table after the first table partition is purged.
12. The non-transitory machine-readable storage medium of claim 11 , wherein the future table partition is an empty table partition at the time the identified database entry is copied to the future table partition.
13. The non-transitory machine-readable storage medium of claim 11 , further comprising instructions to update a cache to include the updated version of the identified database entry, wherein the cache stores latest versions of each database entry in the database table.
14. The non-transitory machine-readable storage medium of claim 13 , further comprising instructions to query the database table to locate the dummy database entry and to update the cache with database entries stored in the future table partition.
15. The non-transitory machine-readable storage medium of claim 11 , wherein the database table is a columnar database table.
16. The non-transitory machine-readable storage medium of claim 11 , wherein the database table comprises a log-structured merge-tree data structure.
17. The non-transitory machine-readable storage medium of claim 11 , further comprising instructions to copy updated versions of a plurality of database entries identified in the first table partition to a plurality of future table partitions of the database table, and wherein the dummy database entry stores identifiers for the plurality of future table partitions.
18. A computing device comprising a processor to:
identify a first table partition of a database table to be purged by identifying an oldest table partition of the database table, wherein the first table partition is one of a plurality of table partitions of the database table, and wherein the plurality of table partitions are separated according to time ranges;
identify a database entry in the first table partition, wherein a latest version of the identified database entry in the database table is stored in the first table partition, and wherein the identified database entry is to be copied;
copy an updated version of the identified database entry to a future table partition of the database table;
update a cache to include the updated version of the identified database entry;
purge the first table partition;
create a dummy database entry in a second table partition of the database table, wherein the dummy database entry stores an identifier for the future table partition, and wherein the second table partition is a second oldest table partition of the database table and becomes the oldest table partition of the database table after the first table partition is purged; and
query the database table to locate the dummy database entry and update the cache with database entries stored in the future table partition, wherein the cache stores the latest versions of each database entry in the database table.
19. The computing device of claim 18 , wherein the future table partition is an empty table partition at the time the identified database entry is copied to the future table partition.
20. The computing device of claim 18 , wherein the database table is a columnar database table that comprises a log-structured merge-tree data structure.