Kbase 17087: index compression performed by conv67 creates free blocks
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
10/05/1998 |
|
index compression performed by conv67 creates free blocks
After moving from Version 6 to Version 7, customers may indicate
their database doesn't seem to be growing, depsite continued use
and a prior history of a certain amount of growth per day. One
reason for this may be due to the amount of blocks freed by conv67.
The proutil -C conv67 utility will compress indices, thus freeing
up blocks. Blocks which were freed up due to the compressed
index will be reused as needed. These blocks become "free"
blocks. A free block can be converted to either a Data (RM) or
an Index block.
To go further, here's the lifecycle of a block in the version 7
and version 8 database, but first some definitions:
EMPTY - A block above the high water mark. Contains no
information
FREE - Same as empty, but below the high water mark
INDEX - A block containing index information
RM - A block which contains record information
A block starts out as an EMPTY block. Once the high water mark
goes above the block, it gets converted to a FREE block and is
put on the FREE chain. It won't be on the free chain for long;
the reason the high water mark moved was because the free chain
was exhausted. A FREE block can become either an INDEX block or
an RM block. If the block becomes an INDEX block, then at a
later time the block may be converted back to a FREE block by
doing an index rebuild. If the block becomes a RM block, then it
will remain an RM block for the life of the database.
Progress Software Technical Support Note # 17087