Online, efficient and cost-optimized database index consistency checks

A non-transitory computer-readable storage medium coupled to one or more processors and having instructions stored thereon which, when executed by the one or more processors, cause the one or more processors to perform operations for database consistency checks in database systems, the operations comprising:

• reading a page of a plurality of pages stored in a database system, each page storing rows of data;
• for a first index row of a plurality of index rows of a first page of the plurality of pages, determining that the first index row is absent from being recorded in a hash table, and in response:
• storing a first record of the first index row in the hash table, the first record comprising a first hash value representative of the first index row, the first hash value being determined through hashing using an object identifier that identifies a table and an index identifier that identifies an index of the table, the first hash value pointing to a second hash value determined through hashing a page identifier based on a bucket count;
• for a first data row of a plurality of data rows of a second page of the plurality of pages:
• providing a second index row based on one or more values of one or more fields of the first data row, and
• determining that the second index row is recorded in the hash table as the first index row in the first record, and in response:
• removing the first record from the hash table;
• and
• outputting index consistency results based on the hash table.

A system, comprising:

• a computing device;
• and
• a computer-readable storage device coupled to the computing device and having instructions stored thereon which, when executed by the computing device, cause the computing device to perform operations for database consistency checks in database systems, the operations comprising:
• reading a page of a plurality of pages stored in a database system, each page storing rows of data;
• for a first index row of a plurality of index rows of a first page of the plurality of pages, determining that the first index row is absent from being recorded in a hash table, and in response:
• storing a first record of the first index row in the hash table, the first record comprising a first hash value representative of the first index row, the first hash value being determined through hashing using an object identifier that identifies a table and an index identifier that identifies an index of the table, the first hash value pointing to a second hash value determined through hashing a page identifier based on a bucket count;
• for a first data row of a plurality of data rows of a second page of the plurality of pages:
• providing a second index row based on one or more values of one or more fields of the first data row, and
• determining that the second index row is recorded in the hash table as the first index row in the first record, and in response:
• removing the first record from the hash table;
• and
• outputting index consistency results based on the hash table.