SqliteVtabIntegrityCallback

If the iVersion for an sqlite3_module is 4 or more and the xIntegrity method is not NULL, then the PRAGMA integrity_check and PRAGMA quick_check commands will invoke xIntegrity as part of its processing. If the xIntegrity method writes an error message string into the fifth parameter, then PRAGMA integrity_check will report that error as part of its output. So, in other words, the xIntegrity method allows the PRAGMA integrity_check command to verify the integrity of content stored in a virtual table.

The xIntegrity method should normally return SQLITE_OK - even if it finds problems in the content of the virtual table. So, for example, if the inverted index for FTS5 is found to be internally inconsistent, then the xIntegrity method should write an appropriate error message into the pzErr parameter and return SQLITE_OK. But if the xIntegrity method is unable to complete its evaluation of the virtual table content due to running out of memory, then it should return SQLITE_NOMEM.

The xIntegrity Method