Methods and apparatus for persistent data structures
A method may include storing at least a portion of a metadata buffer of a persistent data structure in volatile memory, and storing at least a portion of a data buffer of the persistent data structure in persistent memory. A system may include a processor, a volatile memory coupled to the processor, and a persistent memory coupled to the processor. The processor may be configured to execute procedures including storing at least a portion of a metadata buffer of a persistent data structure in volatile memory, and storing at least a portion of a data buffer of the persistent data structure in persistent memory. A method may include storing at least a portion of a transient part of a persistent data structure in volatile memory, and storing at least a portion of a persistent part of the persistent data structure in persistent memory.
1. A method of storing data in a data processing system, the method comprising:
storing at least a portion of a metadata element of a persistent data structure in volatile memory; and
storing at least a portion of a data element of the persistent data structure in persistent memory;
wherein the metadata element comprises information to maintain at least one of an order or a consistency of the persistent data structure.
2. The method of claim 1 , wherein:
the portion of the metadata element stored in volatile memory is stored in a first container; and
the portion of the data element stored in persistent memory is stored in a second container that is independent of the first container.
3. The method of claim 1 , wherein the portion of the metadata element stored in volatile memory includes transient data.
4. The method of claim 3 , wherein the transient data comprises an in-memory link.
5. The method of claim 3 , wherein the transient data comprises the state of at least one of the metadata element or the data element.
6. The method of claim 3 , wherein the transient data comprises a page pointer.
7. The method of claim 1 , wherein the portion of the data element stored in persistent memory includes persistent state data.
8. The method of claim 7 , wherein the persistent state data comprises a journal.
9. The method of claim 1 , wherein the persistent data structure comprises a first persistent data structure, the metadata element comprises a first metadata element, and the data element comprises a first data element, the method further comprising:
storing at least a portion of a second metadata element of a second persistent data structure in volatile memory; and
storing at least a portion of a second data element of the second persistent data structure in persistent memory.
10. The method of claim 9 , further comprising:
maintaining a first link between the first metadata element and the first data element;
maintaining a second link between the second metadata element and the second data element; and
maintaining a third link between the first metadata element and the second metadata element.
11. The method of claim 1 , wherein the metadata element comprises a link from the metadata element to the data element.
12. A system comprising:
a processor;
a volatile memory coupled to the processor; and
a persistent memory coupled to the processor;
wherein the processor is configured to execute procedures comprising:
storing at least a portion of a metadata element of a persistent data structure in volatile memory; and
storing at least a portion of a data element of the persistent data structure in persistent memory; and
wherein the metadata element comprises an in-memory link.
13. The system of claim 12 , wherein the portion of the metadata element stored in volatile memory includes transient data.
14. The system of claim 12 , wherein the portion of the data element stored in persistent memory includes persistent state data.
15. The system of claim 12 , wherein the in-memory link comprises one or more of a previous link or a next link.
16. The system of claim 12 , wherein the in-memory link comprises one or more of a sibling link or a child link.
17. The system of claim 12 , wherein the in-memory link comprises a link to maintain a pending queue.
18. A method of storing a persistent data structure in a data processing system, the method comprising:
storing at least a portion of a transient part of the persistent data structure in volatile memory; and
storing at least a portion of a persistent part of the persistent data structure in persistent memory;
wherein the portion of the transient part of the persistent data structure comprises information to indicate a clean state of a buffer.
19. The method of claim 18 , wherein:
the transient part of the persistent data structure comprises a metadata element; and
the persistent part of the persistent data structure comprises a data element.
20. The method of claim 18 , wherein the transient part of the persistent data structure comprises state data.