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Add the full set of comparison functions for type TID, including a btree

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opclass.  This is not so much because anyone's likely to create an index
on TID, as that sorting TIDs can be useful.  Also added max and min
aggregates while at it, so that one can investigate the clusteredness of
a table with queries like SELECT min(ctid), max(ctid) FROM tab WHERE ...
Greg Stark and Tom Lane
This commit is contained in:
Tom Lane
2006-07-21 20:51:33 +00:00
parent bc660c4237
commit 0144eb92bb
9 changed files with 167 additions and 51 deletions
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104
src/backend/utils/adt/tid.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/tid.c,v 1.53 2006/07/14 05:28:28 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/tid.c,v 1.54 2006/07/21 20:51:32 tgl Exp $
*
* NOTES
* input routine largely stolen from boxin().
@ -98,16 +98,11 @@ Datum
tidout(PG_FUNCTION_ARGS)
{
ItemPointer itemPtr = PG_GETARG_ITEMPOINTER(0);
BlockId blockId;
BlockNumber blockNumber;
OffsetNumber offsetNumber;
char buf[32];
if (!ItemPointerIsValid(itemPtr))
PG_RETURN_CSTRING(pstrdup("()"));
blockId = &(itemPtr->ip_blkid);
blockNumber = BlockIdGetBlockNumber(blockId);
blockNumber = BlockIdGetBlockNumber(&(itemPtr->ip_blkid));
offsetNumber = itemPtr->ip_posid;
/* Perhaps someday we should output this as a record. */
@ -163,15 +158,36 @@ tidsend(PG_FUNCTION_ARGS)
* PUBLIC ROUTINES *
*****************************************************************************/
static int32
tid_cmp_internal(ItemPointer arg1, ItemPointer arg2)
{
/*
* Don't use ItemPointerGetBlockNumber or ItemPointerGetOffsetNumber here,
* because they assert ip_posid != 0 which might not be true for a
* user-supplied TID.
*/
BlockNumber b1 = BlockIdGetBlockNumber(&(arg1->ip_blkid));
BlockNumber b2 = BlockIdGetBlockNumber(&(arg2->ip_blkid));
if (b1 < b2)
return -1;
else if (b1 > b2)
return 1;
else if (arg1->ip_posid < arg2->ip_posid)
return -1;
else if (arg1->ip_posid > arg2->ip_posid)
return 1;
else
return 0;
}
Datum
tideq(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(BlockIdGetBlockNumber(&(arg1->ip_blkid)) ==
BlockIdGetBlockNumber(&(arg2->ip_blkid)) &&
arg1->ip_posid == arg2->ip_posid);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) == 0);
}
Datum
@ -180,11 +196,73 @@ tidne(PG_FUNCTION_ARGS)
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(BlockIdGetBlockNumber(&(arg1->ip_blkid)) !=
BlockIdGetBlockNumber(&(arg2->ip_blkid)) ||
arg1->ip_posid != arg2->ip_posid);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) != 0);
}
Datum
tidlt(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) < 0);
}
Datum
tidle(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) <= 0);
}
Datum
tidgt(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) > 0);
}
Datum
tidge(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_BOOL(tid_cmp_internal(arg1,arg2) >= 0);
}
Datum
bttidcmp(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_INT32(tid_cmp_internal(arg1, arg2));
}
Datum
tidlarger(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_ITEMPOINTER(tid_cmp_internal(arg1,arg2) >= 0 ? arg1 : arg2);
}
Datum
tidsmaller(PG_FUNCTION_ARGS)
{
ItemPointer arg1 = PG_GETARG_ITEMPOINTER(0);
ItemPointer arg2 = PG_GETARG_ITEMPOINTER(1);
PG_RETURN_ITEMPOINTER(tid_cmp_internal(arg1,arg2) <= 0 ? arg1 : arg2);
}
/*
* Functions to get latest tid of a specified tuple.
*