Check Pages with -cd and -cD

The -cd option reads all pages, excluding blobpages and sbpages, from the tblspace for the specified database, table, or fragment and checks each page for consistency. It checks entries in the bitmap page against the pages to verify mapping.

If the database contains fragmented tables, but you do not specify a fragment, the option checks all fragments in the table. If you do not specify a table, it checks all tables in the database. (The -pd option displays a hexadecimal dump of specified pages but does not check for consistency.)

For both the -cd and -cD options, the oncheck utility locks each table as it checks the indexes for the table. To repair the pages, specify oncheck -cd -y or -cD -y.

The -cD option performs checks similar to those performed when you use the -cd option, but it includes a consistency check of blobpages. The -cD option checks only the header of each blobpage for consistency. Because oncheck does not read the entire page, it does not compare beginning time stamps (stored in the header) with ending time stamps (stored at the end of a blobpage). The -cD -y option also cleans up orphaned simple large objects in blobspaces (which could occur after a rollback across several log files).

If tables are fragmented on multiple partitions in the same dbspace, the oncheck -cd and oncheck -cD commands show the partition names. The following example shows typical output for a table that has fragments in multiple partitions in the same dbspace:

TBLspace data check for multipart:informix.t1
              Table fragment partition part_1 in DBspace dbs1
              Table fragment partition part_2 in DBspace dbs1
              Table fragment partition part_3 in DBspace dbs1
              Table fragment partition part_4 in DBspace dbs1
              Table fragment partition part_5 in DBspace dbs1

To monitor blobspace blobpages, refer to oncheck -pB. (See Display Blobspace Statistics with -pB).

The following example checks the data rows, including simple large objects and smart large objects, in the catalog table:

oncheck -cD superstores_demo:catalog

If oncheck finds an inconsistency, it displays a message similar to the following one:

BAD PAGE 2:28: pg_addr 2:28 != bp-> bf_pagenum 2:69

The physical address 2:28 represents page 28 of chunk number 2. If oncheck finds no inconsistencies, it displays a header similar to the following one for each table that it checks:

TBLSPACE data check for stores_demo:informix.customer

If you specify a single fragment, oncheck displays a single header for that fragment. The oncheck utility displays a header similar to the following one for fragmented tables, one per fragment:

TBLspace data check for stores_demo:informix.tab1
 Table fragment in DBspace db1

If an index that uses an access method provided by a DataBlade module cannot find the access method, you receive the following message:

-9845 Access method access_method_name does not exist in database. 
Ensure that the DataBlade installation was successful.