NonStop SQL/MP Reference Manual

NonStop SQL/MP Reference Manual—142115
C-86
Considerations—CONTROL TABLE
The buffer is flushed to the disk process, which puts the buffer in cache and writes
the data to disk when the table is closed or, for audited tables, when the transaction
commits. For nonaudited tables, the buffer is written to disk when the FREE
RESOURCES statement executes.
•
Conditions that prevent buffering for INSERTs and UPDATEs
SQL does not buffer operations if any of the conditions described in the following
table occur.
•
Using VSBB with cursor operations
Condition
Prevents
Buffering
for UPDATES
Prevents
Buffering
for INSERTS
A table is not a base table
(operations for index maintenance
are not buffered).
XX
A table has at least one cursor
defined by the same process.
N.A. X
A relative or entry-sequenced table is
indexed.
N.A. X
An operation on a relative table does
not occur at end-of-file.
N.A. X
An operation on a relative or entry-
sequenced table includes the
RETURNING clause with a host
variable.
N.A. X
A nonaudited table has one or more
indexes, and the operation involves
variable length character columns.
XN.A.
A table has more than one cursor
defined by the same process, or an
alternate access path is selected.
XN.A.
SEQUENTIAL READ OFF is in
effect for the table.
XN.A.
SEQUENTIAL UPDATE OFF is in
effect for the table.
XN.A.
SEQUENTIAL INSERT OFF is in
effect for the table.
N.A. X
An INSERT or UPDATE operation
is mixed with other operations
instead of occurring in sequence.
XX
The INSERT or UPDATE operation
is not in sequential order.
XX