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Add temporal PRIMARY KEY and UNIQUE constraints

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Add WITHOUT OVERLAPS clause to PRIMARY KEY and UNIQUE constraints.
These are backed by GiST indexes instead of B-tree indexes, since they
are essentially exclusion constraints with = for the scalar parts of
the key and && for the temporal part.

Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com
This commit is contained in:
Peter Eisentraut
2024-01-24 15:43:41 +01:00
parent 74a7306310
commit 46a0cd4cef
34 changed files with 1135 additions and 52 deletions
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28
src/backend/parser/parse_utilcmd.c
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@ -1716,6 +1716,7 @@ generateClonedIndexStmt(RangeVar *heapRel, Relation source_idx,
index->unique = idxrec->indisunique;
index->nulls_not_distinct = idxrec->indnullsnotdistinct;
index->primary = idxrec->indisprimary;
index->iswithoutoverlaps = (idxrec->indisprimary || idxrec->indisunique) && idxrec->indisexclusion;
index->transformed = true; /* don't need transformIndexStmt */
index->concurrent = false;
index->if_not_exists = false;
@ -1765,7 +1766,9 @@ generateClonedIndexStmt(RangeVar *heapRel, Relation source_idx,
int nElems;
int i;
Assert(conrec->contype == CONSTRAINT_EXCLUSION);
Assert(conrec->contype == CONSTRAINT_EXCLUSION ||
(index->iswithoutoverlaps &&
(conrec->contype == CONSTRAINT_PRIMARY || conrec->contype == CONSTRAINT_UNIQUE)));
/* Extract operator OIDs from the pg_constraint tuple */
datum = SysCacheGetAttrNotNull(CONSTROID, ht_constr,
Anum_pg_constraint_conexclop);
@ -2305,6 +2308,7 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
}
index->nulls_not_distinct = constraint->nulls_not_distinct;
index->isconstraint = true;
index->iswithoutoverlaps = constraint->without_overlaps;
index->deferrable = constraint->deferrable;
index->initdeferred = constraint->initdeferred;
@ -2397,6 +2401,11 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
errmsg("index \"%s\" is not valid", index_name),
parser_errposition(cxt->pstate, constraint->location)));
/*
* Today we forbid non-unique indexes, but we could permit GiST
* indexes whose last entry is a range type and use that to create a
* WITHOUT OVERLAPS constraint (i.e. a temporal constraint).
*/
if (!index_form->indisunique)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
@ -2673,6 +2682,23 @@ transformIndexConstraint(Constraint *constraint, CreateStmtContext *cxt)
notnullcmds = lappend(notnullcmds, notnullcmd);
}
}
if (constraint->without_overlaps)
{
/*
* This enforces that there is at least one equality column
* besides the WITHOUT OVERLAPS columns. This is per SQL
* standard. XXX Do we need this?
*/
if (list_length(constraint->keys) < 2)
ereport(ERROR,
errcode(ERRCODE_SYNTAX_ERROR),
errmsg("constraint using WITHOUT OVERLAPS needs at least two columns"));
/* WITHOUT OVERLAPS requires a GiST index */
index->accessMethod = "gist";
}
}
/*