Sybase 11.9.x-12.5 - Manual (Page 558)

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The Navigation Server has its own error log file where Navigation Server error
messages are written. Refer to the Navigation Server Reference Manual for
details.
extent Every 256-page allocation unit is divided into 32 structures called extents, each
containing 8 contiguous pages. Each extent contains information about those 8
contiguous pages, including a bitmap showing pages in use and a bitmap
showing pages to be deallocated.
foreign key In a table, a column whose data values correspond to the values of a key
column in another table.
index ID The number Adaptive Server uses to uniquely identify (within a database) an
index. The following table shows the index types:
leaf level The bottom of a clustered or nonclustered index. In a clustered index, the leaf
level contains the actual data pages of the table.
logical page The unique address for pages in the context of each database.
MASS Buffers are grouped together to form Memory Address Space Segments
(MASSes). A buffer cache consists of MASSes linked in MRU/LRU (most
recently used/least recently used) chains.
nonclustered index An index that stores key values and points to data. The leaf level points to data
rows rather than containing the data itself.
Object Allocation
Map (OAM) An Object Allocation Map (OAM) contains information about how space is
allocated for Adaptive Server objects. A single OAM page holds information
about up to 250 allocation pages (248 if the object is an IDENTITY column).
Each allocation page for an object has an entry in the OAM pages for that table
or index. The OAM entry for each allocation page stores the number of used
and unused data and index pages on that allocation page.
A maximum of 263 OAM pages are allowed, supporting a maximum of 65,535
allocation units for an object.
Index ID Meaning
0 Actual table data
1 Clustered index
2-250 Nonclustered indexes
255 Text or image page