On 11/26/15 6:49 AM, [email protected] wrote:
Hello,
I would like to test the consistency check function but I have
difficulties inserting certain inconsistencies into the database for
proper testing.
I found a Testscript which uses T_ConsistencyChecker.class and managed
to run it but so far it only tests the following cases:
- Base tables and all associated indexes contain the same number of rows.
- The values and row locations in each index match those of the base
table.
According to the documentation, there are two other cases:
- Base tables are internally consistent.
- All BTREE indexes are internally consistent.
Is it possible to manipulate the base tables and/or the btree indexes
in a way to cause inconsistencies, so I can run this function to find
them?
What would be the error messages of these cases?
Thank you,
Tu
You might start out by using a text editor in order to insert some
garbage into the datafiles which hold the base table and the index.
Those files are located in the seg0 directory of the database. A script
like the following will tell you which datafiles correspond to which
base tables and indexes:
connect 'jdbc:derby:memory:db;create=true';
create table t1( a int );
create index t1_idx on t1( a );
create table t2( a int primary key );
create function toHex( conglomerateNumber bigint )
returns varchar( 10 )
language java parameter style java no sql
external name 'java.lang.Long.toHexString';
select s.schemaName, t.tableName,
'c' || toHex( c.conglomerateNumber ) || '.dat' dataFile,
c.isIndex, c.isConstraint
from sys.systables t, sys.sysconglomerates c, sys.sysschemas s
where t.tablename not like 'SYS%'
and t.tableid = c.tableid
and t.schemaid = s.schemaid
order by tableName, dataFile;
I see the following interesting exceptions being raised by
org.apache.derby.iapi.db.ConsistencyChecker:
SQLState.LANG_INCONSISTENT_ROW_LOCATION (X0XC2)
SQLState.LANG_INDEX_COLUMN_NOT_EQUAL (X0XC1)
SQLState.LANG_INDEX_ROW_COUNT_MISMATCH (X0Y55)
Hope this helps,
-Rick
