Cattell on November 4, 1983 2:27 am
Willie-Sue, February 15, 1985 11:18:15 am PST
Widom, September 3, 1985 6:26:15 pm PDT
Donahue, May 22, 1986 11:34:09 am PDT
DIRECTORY
DBCommon USING [Segment, CacheHandle, TID],
DBStorage USING [TupleHandle];
DBStorageTuple:
CEDAR
DEFINITIONS =
BEGIN
This interface defines a collection of operations on DBStorage.TupleObjects that may be used by storage-level modules that don't export DBStorage.TupleObject. Some modules export DBStorage.TupleObject simply to get read access to the TID without the cost of a procedure call, and use these procedures for other accesses.
InitSegmentTuples:
PUBLIC
PROC [segment: DBCommon.Segment];
Called from DBStorage.AttachSegment to set up the tuple management for the segment.
ConsTupleObject:
PROC [tid: DBCommon.
TID, cacheHint: DBCommon.CacheHandle ←
NIL]
RETURNS [DBStorage.TupleHandle];
Returns a handle for a new tuple object with the given tid and cacheHint.
TIDOfTuple:
PROC [x: DBStorage.TupleHandle]
RETURNS [DBCommon.
TID];
Returns the TID of x.
EqualTuple:
PROC [x, y: DBStorage.TupleHandle]
RETURNS [
BOOLEAN];
Returns TIDOfTuple[x] = TIDOfTuple[y].
NullTupleHandle:
PROC []
RETURNS [DBStorage.TupleHandle];
Returns a TupleHandle x such that TIDOfTuple[x] = NullTID.
No caller should modify the contents of this TupleObject in any way!!!
InvalidateMatchingTuples:
PROC [x: DBStorage.TupleHandle];
For all tuple handles y on active list such that y.tid = x.tid, makes y.tid=NullTID.
IsValidTuple:
PROC [x: DBStorage.TupleHandle]
RETURNS [valid:
BOOL];
IF DBSegment.IsValidTID[x.tid] THEN RETURN [valid: TRUE] ELSE { x.tid ← NullTID; RETURN [valid: FALSE] }
InvalidateTuple:
PROC [x: DBStorage.TupleHandle];
x.tid ← NullTID
CallAfterFinishTransaction:
PROC [s: DBCommon.Segment];
Invalidates (by setting tid = NullTID, cacheHint = NIL) all TupleObjects on the active list that reference segment s.
PrintTupleObject:
PROC [t: DBStorage.TupleHandle];
Prints t to debug stream, without a terminating CR.
CheckState:
PROC [segment: DBCommon.Segment, doPrinting:
BOOLEAN ←
FALSE];
Checks internal state of tuple manager; if doPrinting, also prints contents of tuple manager to debug stream.