3-64 IBM Informix OnLine Database Server Administrator’s Guide
Monitor Blobs in a Blobspace
From the Command Line
From the command line, executetbstat -d to obtain information that is
similarto that displayed by the Dbspaces menu, Info option. However, where
DB-Monitor lists total pages and the number used, tbstat -dlists total pages
and, in thebpages field, the approximate number of free blobpages.
The tilde (~) that precedes thebpages value indicates that this number is
approximate because it is derived from the information stored in the disk
version of the chunk’s free-map page, not the version of the free-map page
stored in shared memory.
Another complication is thattbstat -d does not register a blobpage as
availableuntil the logical log in which a blob deletion occurred is backed up
andthe blobpage is freed. Therefore, if you delete 25 blobs and immediately
executetbstat -d, the newly freed space does not appear in the tbstat output.
Refer topage 7-84 for further information about the tbstat -d display.
From the command line, you also can obtain an accurate picture of the
amountof available space in a blobspace, by executing tbcheck with the -pB
options. This utility gathers its data from the actual blob-storage statistics.
Execute tbcheck -pB with either a database name or a table name as a
parameter. The display reports the following statistics:
■Numberof blobpages used by this table or database in all blobspaces
■Blobpage fullness, by blob, for each blob in this table or database
P Primary chunk.
R Chunk is currently being recovered.
X Newmirror chunk that contains logical log files; a level-0 archive is
needed before the mirror can become active.
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