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Add exclusion constraints, which generalize the concept of uniqueness to

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support any indexable commutative operator, not just equality.  Two rows
violate the exclusion constraint if "row1.col OP row2.col" is TRUE for
each of the columns in the constraint.

Jeff Davis, reviewed by Robert Haas
This commit is contained in:
Tom Lane
2009-12-07 05:22:23 +00:00
parent 8de7472b45
commit 0cb65564e5
43 changed files with 1613 additions and 236 deletions
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87
src/backend/utils/adt/ruleutils.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.315 2009/11/20 20:38:11 tgl Exp $
* $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.316 2009/12/07 05:22:22 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -144,6 +144,7 @@ static void decompile_column_index_array(Datum column_index_array, Oid relId,
StringInfo buf);
static char *pg_get_ruledef_worker(Oid ruleoid, int prettyFlags);
static char *pg_get_indexdef_worker(Oid indexrelid, int colno,
const Oid *excludeOps,
bool attrsOnly, bool showTblSpc,
int prettyFlags);
static char *pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
@ -705,6 +706,7 @@ pg_get_indexdef(PG_FUNCTION_ARGS)
Oid indexrelid = PG_GETARG_OID(0);
PG_RETURN_TEXT_P(string_to_text(pg_get_indexdef_worker(indexrelid, 0,
NULL,
false, false, 0)));
}
@ -718,6 +720,7 @@ pg_get_indexdef_ext(PG_FUNCTION_ARGS)
prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
PG_RETURN_TEXT_P(string_to_text(pg_get_indexdef_worker(indexrelid, colno,
NULL,
colno != 0,
false,
prettyFlags)));
@ -727,7 +730,7 @@ pg_get_indexdef_ext(PG_FUNCTION_ARGS)
char *
pg_get_indexdef_string(Oid indexrelid)
{
return pg_get_indexdef_worker(indexrelid, 0, false, true, 0);
return pg_get_indexdef_worker(indexrelid, 0, NULL, false, true, 0);
}
/* Internal version that just reports the column definitions */
@ -737,14 +740,23 @@ pg_get_indexdef_columns(Oid indexrelid, bool pretty)
int prettyFlags;
prettyFlags = pretty ? PRETTYFLAG_PAREN | PRETTYFLAG_INDENT : 0;
return pg_get_indexdef_worker(indexrelid, 0, true, false, prettyFlags);
return pg_get_indexdef_worker(indexrelid, 0, NULL, true, false, prettyFlags);
}
/*
* Internal workhorse to decompile an index definition.
*
* This is now used for exclusion constraints as well: if excludeOps is not
* NULL then it points to an array of exclusion operator OIDs.
*/
static char *
pg_get_indexdef_worker(Oid indexrelid, int colno,
const Oid *excludeOps,
bool attrsOnly, bool showTblSpc,
int prettyFlags)
{
/* might want a separate isConstraint parameter later */
bool isConstraint = (excludeOps != NULL);
HeapTuple ht_idx;
HeapTuple ht_idxrel;
HeapTuple ht_am;
@ -842,11 +854,17 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
initStringInfo(&buf);
if (!attrsOnly)
appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (",
idxrec->indisunique ? "UNIQUE " : "",
quote_identifier(NameStr(idxrelrec->relname)),
generate_relation_name(indrelid, NIL),
quote_identifier(NameStr(amrec->amname)));
{
if (!isConstraint)
appendStringInfo(&buf, "CREATE %sINDEX %s ON %s USING %s (",
idxrec->indisunique ? "UNIQUE " : "",
quote_identifier(NameStr(idxrelrec->relname)),
generate_relation_name(indrelid, NIL),
quote_identifier(NameStr(amrec->amname)));
else /* currently, must be EXCLUDE constraint */
appendStringInfo(&buf, "EXCLUDE USING %s (",
quote_identifier(NameStr(amrec->amname)));
}
/*
* Report the indexed attributes
@ -917,6 +935,13 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
appendStringInfo(&buf, " NULLS FIRST");
}
}
/* Add the exclusion operator if relevant */
if (excludeOps != NULL)
appendStringInfo(&buf, " WITH %s",
generate_operator_name(excludeOps[keyno],
keycoltype,
keycoltype));
}
}
@ -943,8 +968,12 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
tblspc = get_rel_tablespace(indexrelid);
if (OidIsValid(tblspc))
{
if (isConstraint)
appendStringInfoString(&buf, " USING INDEX");
appendStringInfo(&buf, " TABLESPACE %s",
quote_identifier(get_tablespace_name(tblspc)));
}
}
/*
@ -968,7 +997,10 @@ pg_get_indexdef_worker(Oid indexrelid, int colno,
/* Deparse */
str = deparse_expression_pretty(node, context, false, false,
prettyFlags, 0);
appendStringInfo(&buf, " WHERE %s", str);
if (isConstraint)
appendStringInfo(&buf, " WHERE (%s)", str);
else
appendStringInfo(&buf, " WHERE %s", str);
}
}
@ -1244,6 +1276,43 @@ pg_get_constraintdef_worker(Oid constraintId, bool fullCommand,
break;
}
case CONSTRAINT_EXCLUSION:
{
Oid indexOid = conForm->conindid;
Datum val;
bool isnull;
Datum *elems;
int nElems;
int i;
Oid *operators;
/* Extract operator OIDs from the pg_constraint tuple */
val = SysCacheGetAttr(CONSTROID, tup,
Anum_pg_constraint_conexclop,
&isnull);
if (isnull)
elog(ERROR, "null conexclop for constraint %u",
constraintId);
deconstruct_array(DatumGetArrayTypeP(val),
OIDOID, sizeof(Oid), true, 'i',
&elems, NULL, &nElems);
operators = (Oid *) palloc(nElems * sizeof(Oid));
for (i = 0; i < nElems; i++)
operators[i] = DatumGetObjectId(elems[i]);
/* pg_get_indexdef_worker does the rest */
/* suppress tablespace because pg_dump wants it that way */
appendStringInfoString(&buf,
pg_get_indexdef_worker(indexOid,
0,
operators,
false,
false,
prettyFlags));
break;
}
default:
elog(ERROR, "invalid constraint type \"%c\"", conForm->contype);
break;