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62f34097c8
This follows in the spirit of commit dfb75e478, which created primary
key and uniqueness constraints to improve the visibility of constraints
imposed on the system catalogs. While our catalogs contain many
foreign-key-like relationships, they don't quite follow SQL semantics,
in that the convention for an omitted reference is to write zero not
NULL. Plus, we have some cases in which there are arrays each of whose
elements is supposed to be an FK reference; SQL has no way to model that.
So we can't create actual foreign key constraints to describe the
situation. Nonetheless, we can collect and use knowledge about these
relationships.
This patch therefore adds annotations to the catalog header files to
declare foreign-key relationships. (The BKI_LOOKUP annotations cover
simple cases, but we weren't previously distinguishing which such
columns are allowed to contain zeroes; we also need new markings for
multi-column FK references.) Then, Catalog.pm and genbki.pl are
taught to collect this information into a table in a new generated
header "system_fk_info.h". The only user of that at the moment is
a new SQL function pg_get_catalog_foreign_keys(), which exposes the
table to SQL. The oidjoins regression test is rewritten to use
pg_get_catalog_foreign_keys() to find out which columns to check.
Aside from removing the need for manual maintenance of that test
script, this allows it to cover numerous relationships that were not
checked by the old implementation based on findoidjoins. (As of this
commit, 217 relationships are checked by the test, versus 181 before.)
Discussion: https://postgr.es/m/3240355.1612129197@sss.pgh.pa.us
91 lines
3.4 KiB
C
91 lines
3.4 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_index.h
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* definition of the "index" system catalog (pg_index)
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*
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*
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* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/catalog/pg_index.h
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*
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* NOTES
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* The Catalog.pm module reads this file and derives schema
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* information.
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PG_INDEX_H
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#define PG_INDEX_H
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#include "catalog/genbki.h"
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#include "catalog/pg_index_d.h"
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/* ----------------
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* pg_index definition. cpp turns this into
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* typedef struct FormData_pg_index.
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* ----------------
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*/
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CATALOG(pg_index,2610,IndexRelationId) BKI_SCHEMA_MACRO
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{
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Oid indexrelid BKI_LOOKUP(pg_class); /* OID of the index */
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Oid indrelid BKI_LOOKUP(pg_class); /* OID of the relation it
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* indexes */
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int16 indnatts; /* total number of columns in index */
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int16 indnkeyatts; /* number of key columns in index */
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bool indisunique; /* is this a unique index? */
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bool indisprimary; /* is this index for primary key? */
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bool indisexclusion; /* is this index for exclusion constraint? */
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bool indimmediate; /* is uniqueness enforced immediately? */
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bool indisclustered; /* is this the index last clustered by? */
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bool indisvalid; /* is this index valid for use by queries? */
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bool indcheckxmin; /* must we wait for xmin to be old? */
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bool indisready; /* is this index ready for inserts? */
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bool indislive; /* is this index alive at all? */
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bool indisreplident; /* is this index the identity for replication? */
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/* variable-length fields start here, but we allow direct access to indkey */
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int2vector indkey BKI_FORCE_NOT_NULL; /* column numbers of indexed cols,
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* or 0 */
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#ifdef CATALOG_VARLEN
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oidvector indcollation BKI_LOOKUP_OPT(pg_collation) BKI_FORCE_NOT_NULL; /* collation identifiers */
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oidvector indclass BKI_LOOKUP(pg_opclass) BKI_FORCE_NOT_NULL; /* opclass identifiers */
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int2vector indoption BKI_FORCE_NOT_NULL; /* per-column flags
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* (AM-specific meanings) */
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pg_node_tree indexprs; /* expression trees for index attributes that
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* are not simple column references; one for
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* each zero entry in indkey[] */
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pg_node_tree indpred; /* expression tree for predicate, if a partial
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* index; else NULL */
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#endif
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} FormData_pg_index;
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/* ----------------
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* Form_pg_index corresponds to a pointer to a tuple with
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* the format of pg_index relation.
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* ----------------
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*/
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typedef FormData_pg_index *Form_pg_index;
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DECLARE_INDEX(pg_index_indrelid_index, 2678, on pg_index using btree(indrelid oid_ops));
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#define IndexIndrelidIndexId 2678
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DECLARE_UNIQUE_INDEX_PKEY(pg_index_indexrelid_index, 2679, on pg_index using btree(indexrelid oid_ops));
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#define IndexRelidIndexId 2679
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/* indkey can contain zero (InvalidAttrNumber) to represent expressions */
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DECLARE_ARRAY_FOREIGN_KEY_OPT((indrelid, indkey), pg_attribute, (attrelid, attnum));
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#ifdef EXPOSE_TO_CLIENT_CODE
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/*
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* Index AMs that support ordered scans must support these two indoption
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* bits. Otherwise, the content of the per-column indoption fields is
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* open for future definition.
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*/
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#define INDOPTION_DESC 0x0001 /* values are in reverse order */
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#define INDOPTION_NULLS_FIRST 0x0002 /* NULLs are first instead of last */
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#endif /* EXPOSE_TO_CLIENT_CODE */
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#endif /* PG_INDEX_H */
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