Integrating tablespaces with different block sizes
Provided herein is a mechanism that allows a given database system to access data blocks from another database system, where data blocks from the given database system and data blocks from the other database system have different sizes. According to an aspect of the present invention, a tablespace in the other database system contained the data blocks. The tablespace is detached from the other database system and integrated into the given database, which is capable of processing data stored in data blocks of a different sizes.
1. A method for database systems to access data from other database systems, the method comprising the steps of:
a first database system directly storing first database records in first data blocks having a first data block size;
concurrently with said first database system directly storing first database records in first data blocks having a first data block size, said first database system directly accessing a copy of second data blocks in which a second database system directly stored second database records;
said second data blocks having at least one data block with a second data block size different than said first data block size;
wherein each block of said first data blocks and of said second data blocks is an atomic unit of storage space allocated within a file to store one or more records of a database;
the first database system generating metadata that specifies a plurality of block sizes for data blocks directly accessible to said first database system;
wherein said metadata defines tablespaces and specifies for each tablespace of said tablespaces a particular data block size for data blocks in said tablespace;
integrating said copy of said second data blocks within said first data base system as at least one tablespace that includes said copy of said second data blocks; and
wherein the step of integrating includes modifying said metadata to reflect said second data block size for said at least one tablespace.
2. The method of claim 1 , wherein the step of accessing a copy of second data blocks includes storing user data in said copy of said second data blocks.
3. The method of claim 1 , wherein the method further includes the step of detaching one or more tablespaces from said second database system, wherein said one or more tablespaces include said second data blocks.
4. The method of claim 1 , wherein each data block of said copy of said second data blocks has said second data block size.
5. The method of claim 1 , wherein said first database system is a data warehouse and said second database system is a source database system for said data warehouse.
6. The method of claim 5 , further including the step of integrating said copy of said second data blocks within said data warehouse as a tablespace that includes said copy of said second data blocks.
7. The method of claim 1 , wherein said first database system includes a buffer cache in which said first database system stores data blocks of multiple sizes; and
wherein said method further includes the step of concurrently storing said first data blocks and said second data blocks in said buffer cache.
8. A computer-readable medium carrying one or more sequences of instructions for database systems to access data from other database systems, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:
a first database system directly storing first database records in first data blocks having a first data block size;
concurrently with said first database system directly storing first database records in first data blocks having a first data block size, said first database system directly accessing a copy of second data blocks in which a second database system directly stored second database records;
said second data blocks having at least one data block with a second data block size different than said first data block size;
wherein each block of said first data blocks and of said second data blocks is an atomic unit of storage space allocated within a file to store one or more records of a database;
the first database system generating metadata that specifies a plurality of block sizes for data blocks directly accessible to said first database system;
wherein said metadata defines tablespaces and specifies for each tablespace of said tablespaces a particular data block size for data blocks in said tablespace;
integrating said copy of said second data blocks within said first database system as at least one tablespace that includes said copy of said second data blocks; and
wherein the step of integrating includes modifying said metadata to reflect said second data block size for said at least one tablespace.
9. The computer-readable medium of claim 8 , wherein the step of accessing a copy of second data blocks includes storing user data in said copy of said second data blocks.
10. The computer-readable medium of claim 8 , wherein the computer-readable medium further includes instructions for performing the step of detaching one or more tablespaces from said second database system, wherein said one or more tablespaces include said second data blocks.
11. The computer-readable medium of claim 8 , wherein each data block of said copy of said second data blocks has said second data block size.
12. The computer-readable medium of claim 8 , wherein said first database system is a data warehouse and said second database system is a source database system for said data warehouse.
13. The computer-readable medium of claim 12 , further including instructions for performing the step of integrating said copy of said second data blocks within said data warehouse as a tablespace that includes said copy of said second data blocks.
14. The computer-readable medium of claim 8 ,
wherein said first database system includes a buffer cache in which said first database system stores data blocks of multiple sizes; and
wherein said computer-readable medium further includes the step of concurrently storing said first data blocks and said second data blocks in said buffer cache.
15. The method of claim 7 ,
wherein said buffer cache comprises first buffers for storing buffers of said first data block size and second buffers for storing buffers of said second data block size; and
wherein said first buffers are of a different size than said second buffers.
16. The computer-readable medium of claim 14 ,
wherein said buffer cache comprises first buffers for storing buffers of said first data block size and second buffers for storing buffers of said second data block size; and
wherein said first buffers are of a different size than said second buffers.