IBM 000-8697 Manual Do Utilizador

IBM Informix OnLine Database Server Administrator’s Guide

If you prefer to use a tblspace number and page number, the tblspace number
is stored as a decimal in the partnum column of the systables table. Use the

HEX

 function to obtain the value as a hexadecimal:

SELECT HEX(partnum) FROM systables

WHERE tabname = tablename

You can calculate the page number from the hexadecimal value of the rowid
as follows:

■

The two right-most digits of the hexadecimal rowid refer to the slot-
table entry number for this row.

■

The remaining digits define the page number.

For further information about tbcheck -pp syntax, refer to

further information about tbcheck -pp output, refer to

.

Monitor extents to check for chunk fragmentation (tbcheck -pe) or to
determine disk usage by table. Temporary tables are not monitored. Refer to

From the command line, execute tbcheck -pt with a database name or table
name parameter to obtain the following information for each table:

■

Number of extents

■

First extent size

■

Next extent size

Refer to

 for further information about the tbcheck -pt output.

Execute tbcheck -pe to obtain the physical layout of information in the
chunk. The chunk layout is sequential, and the number of pages dedicated to
each table is shown. The following information displays:

■

Dbspace name, owner, and date created

■

Usage of each chunk in the dbspace, by chunk number

If OnLine is unable to allocate an extent in a chunk despite an adequate
number of free pages, the chunk might be badly fragmented.