IBM 000-8697 Manual de usuario descargar pdf (Pagina 188)

100

101

2-94 IBM Informix OnLine Database Server Administrator’s Guide

OnLine Limits for Chunks

The size of each chunk entry on the chunk-tracking page is the length of the

chunk pathname plus 29 bytes. The available space on the tracking page is

BUFFSIZE minus 28 bytes. As you calculate the number of possible chunk

entries,rememberthat each chunkentrymightrequireuptothreeadditional

bytes to accommodate 4-byte alignment. In the example calculation that

follows, it is assumed that all chunk pathnames are the same size, 10 bytes,

and the page size is two kilobytes:

Each chunk pathname is 10 bytes.

Additional chunk information requires 29 bytes.

Each chunk entry requires a total of 39 bytes.

For 4-byte alignment, each chunk entry requires a total of 40

bytes.

BUFFSIZE is equal to 2 kilobytes or 2048 bytes.

Space available on the chunk-tracking page

is equal to 2048 - 28 or 2020 bytes.

The maximum number of chunk entries that can fit on the chunk-

tracking page is equal to 2020/40 or 50.

Toavoiddifﬁcultiesthatmightoccurifyourunoutofspaceforchunkentries

or if youstart to exceedthemaximum numberofavailable ﬁles,followthese

suggestions:

■ Select short chunk pathnames.

■ Create large chunks.

Add chunks only as needed. You can easily add chunks during OnLine

operation. However, if you over-allocate chunks to a blobspace or dbspace

when you ﬁrst create it, the space remains tied up but unused. You cannot

drop or move individual chunks from a blobspace or dbspace.

1 2 ... 183 184 185 186 187 188 189 190 191 192 193 ... 701 702

Comentarios a estos manuales

Sin comentarios

IBM 000-8697 Manual de usuario Pagina 188

Comentarios a estos manuales

Relacionado con productos y manuales para Software de base de IBM 000-8697