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Remove catalog function currtid()

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currtid() and currtid2() are an undocumented set of functions whose sole
known user is the Postgres ODBC driver, able to retrieve the latest TID
version for a tuple given by the caller of those functions.

As used by Postgres ODBC, currtid() is a shortcut able to retrieve the
last TID loaded into a backend by passing an OID of 0 (magic value)
after a tuple insertion.  This is removed in this commit, as it became
obsolete after the driver began using "RETURNING ctid" with inserts, a
clause supported since Postgres 8.2 (using RETURNING is better for
performance anyway as it reduces the number of round-trips to the
backend).

currtid2() is still used by the driver, so this remains around for now.
Note that this function is kept in its original shape for backward
compatibility reasons.

Per discussion with many people, including Andres Freund, Peter
Eisentraut, Álvaro Herrera, Hiroshi Inoue, Tom Lane and myself.

Bump catalog version.

Discussion: https://postgr.es/m/20200603021448.GB89559@paquier.xyz
This commit is contained in:
Michael Paquier 2020-11-25 12:18:26 +09:00
parent 660b89928d
commit 7b94e99960
7 changed files with 56 additions and 133 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/backend/executor/nodeModifyTable.c
View File

@ -645,10 +645,7 @@ ExecInsert(ModifyTableState *mtstate,
}
if (canSetTag)
{
(estate->es_processed)++;
setLastTid(&slot->tts_tid);
}
/*
* If this insert is the result of a partition key update that moved the

137
src/backend/utils/adt/tid.c
View File

@ -47,6 +47,8 @@
#define DELIM ','
#define NTIDARGS 2
static ItemPointer currtid_for_view(Relation viewrel, ItemPointer tid);
/* ----------------------------------------------------------------
* tidin
* ----------------------------------------------------------------
@ -275,12 +277,44 @@ hashtidextended(PG_FUNCTION_ARGS)
* Maybe these implementations should be moved to another place
*/
static ItemPointerData Current_last_tid = {{0, 0}, 0};
void
setLastTid(const ItemPointer tid)
/*
* Utility wrapper for current CTID functions.
* Returns the latest version of a tuple pointing at "tid" for
* relation "rel".
*/
static ItemPointer
currtid_internal(Relation rel, ItemPointer tid)
{
Current_last_tid = *tid;
ItemPointer result;
AclResult aclresult;
Snapshot snapshot;
TableScanDesc scan;
result = (ItemPointer) palloc(sizeof(ItemPointerData));
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
RelationGetRelationName(rel));
if (rel->rd_rel->relkind == RELKIND_VIEW)
return currtid_for_view(rel, tid);
if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
elog(ERROR, "cannot look at latest visible tid for relation \"%s.%s\"",
get_namespace_name(RelationGetNamespace(rel)),
RelationGetRelationName(rel));
ItemPointerCopy(tid, result);
snapshot = RegisterSnapshot(GetLatestSnapshot());
scan = table_beginscan_tid(rel, snapshot);
table_tuple_get_latest_tid(scan, result);
table_endscan(scan);
UnregisterSnapshot(snapshot);
return result;
}
/*
@ -288,7 +322,7 @@ setLastTid(const ItemPointer tid)
* CTID should be defined in the view and it must
* correspond to the CTID of a base relation.
*/
static Datum
static ItemPointer
currtid_for_view(Relation viewrel, ItemPointer tid)
{
TupleDesc att = RelationGetDescr(viewrel);
@ -338,12 +372,12 @@ currtid_for_view(Relation viewrel, ItemPointer tid)
rte = rt_fetch(var->varno, query->rtable);
if (rte)
{
Datum result;
ItemPointer result;
Relation rel;
result = DirectFunctionCall2(currtid_byreloid,
ObjectIdGetDatum(rte->relid),
PointerGetDatum(tid));
table_close(viewrel, AccessShareLock);
rel = table_open(rte->relid, AccessShareLock);
result = currtid_internal(rel, tid);
table_close(rel, AccessShareLock);
return result;
}
}
@ -352,56 +386,14 @@ currtid_for_view(Relation viewrel, ItemPointer tid)
}
}
elog(ERROR, "currtid cannot handle this view");
return (Datum) 0;
}
Datum
currtid_byreloid(PG_FUNCTION_ARGS)
{
Oid reloid = PG_GETARG_OID(0);
ItemPointer tid = PG_GETARG_ITEMPOINTER(1);
ItemPointer result;
Relation rel;
AclResult aclresult;
Snapshot snapshot;
TableScanDesc scan;
result = (ItemPointer) palloc(sizeof(ItemPointerData));
if (!reloid)
{
*result = Current_last_tid;
PG_RETURN_ITEMPOINTER(result);
}
rel = table_open(reloid, AccessShareLock);
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
RelationGetRelationName(rel));
if (rel->rd_rel->relkind == RELKIND_VIEW)
return currtid_for_view(rel, tid);
if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
elog(ERROR, "cannot look at latest visible tid for relation \"%s.%s\"",
get_namespace_name(RelationGetNamespace(rel)),
RelationGetRelationName(rel));
ItemPointerCopy(tid, result);
snapshot = RegisterSnapshot(GetLatestSnapshot());
scan = table_beginscan_tid(rel, snapshot);
table_tuple_get_latest_tid(scan, result);
table_endscan(scan);
UnregisterSnapshot(snapshot);
table_close(rel, AccessShareLock);
PG_RETURN_ITEMPOINTER(result);
return NULL;
}
/*
* currtid_byrelname
* Get the latest tuple version of the tuple pointing at a CTID, for a
* given relation name.
*/
Datum
currtid_byrelname(PG_FUNCTION_ARGS)
{
@ -410,35 +402,12 @@ currtid_byrelname(PG_FUNCTION_ARGS)
ItemPointer result;
RangeVar *relrv;
Relation rel;
AclResult aclresult;
Snapshot snapshot;
TableScanDesc scan;
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = table_openrv(relrv, AccessShareLock);
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, get_relkind_objtype(rel->rd_rel->relkind),
RelationGetRelationName(rel));
if (rel->rd_rel->relkind == RELKIND_VIEW)
return currtid_for_view(rel, tid);
if (!RELKIND_HAS_STORAGE(rel->rd_rel->relkind))
elog(ERROR, "cannot look at latest visible tid for relation \"%s.%s\"",
get_namespace_name(RelationGetNamespace(rel)),
RelationGetRelationName(rel));
result = (ItemPointer) palloc(sizeof(ItemPointerData));
ItemPointerCopy(tid, result);
snapshot = RegisterSnapshot(GetLatestSnapshot());
scan = table_beginscan_tid(rel, snapshot);
table_tuple_get_latest_tid(scan, result);
table_endscan(scan);
UnregisterSnapshot(snapshot);
/* grab the latest tuple version associated to this CTID */
result = currtid_internal(rel, tid);
table_close(rel, AccessShareLock);

1
src/include/access/heapam.h
View File

@ -129,7 +129,6 @@ extern bool heap_hot_search_buffer(ItemPointer tid, Relation relation,
bool *all_dead, bool first_call);
extern void heap_get_latest_tid(TableScanDesc scan, ItemPointer tid);
extern void setLastTid(const ItemPointer tid);
extern BulkInsertState GetBulkInsertState(void);
extern void FreeBulkInsertState(BulkInsertState);

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 202011241
#define CATALOG_VERSION_NO 202011251
#endif

3
src/include/catalog/pg_proc.dat
View File

@ -2549,9 +2549,6 @@
{ oid => '1292',
proname => 'tideq', proleakproof => 't', prorettype => 'bool',
proargtypes => 'tid tid', prosrc => 'tideq' },
{ oid => '1293', descr => 'latest tid of a tuple',
proname => 'currtid', provolatile => 'v', proparallel => 'u',
prorettype => 'tid', proargtypes => 'oid tid', prosrc => 'currtid_byreloid' },
{ oid => '1294', descr => 'latest tid of a tuple',
proname => 'currtid2', provolatile => 'v', proparallel => 'u',
prorettype => 'tid', proargtypes => 'text tid',

32
src/test/regress/expected/tid.out
View File

@ -15,21 +15,13 @@ SELECT max(ctid) FROM tid_tab;
(1 row)
TRUNCATE tid_tab;
-- Tests for currtid() and currtid2() with various relation kinds
-- Tests for currtid2() with various relation kinds
-- Materialized view
CREATE MATERIALIZED VIEW tid_matview AS SELECT a FROM tid_tab;
SELECT currtid('tid_matview'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: tid (0, 1) is not valid for relation "tid_matview"
SELECT currtid2('tid_matview'::text, '(0,1)'::tid); -- fails
ERROR: tid (0, 1) is not valid for relation "tid_matview"
INSERT INTO tid_tab VALUES (1);
REFRESH MATERIALIZED VIEW tid_matview;
SELECT currtid('tid_matview'::regclass::oid, '(0,1)'::tid); -- ok
currtid
---------
(0,1)
(1 row)
SELECT currtid2('tid_matview'::text, '(0,1)'::tid); -- ok
currtid2
----------
@ -40,12 +32,6 @@ DROP MATERIALIZED VIEW tid_matview;
TRUNCATE tid_tab;
-- Sequence
CREATE SEQUENCE tid_seq;
SELECT currtid('tid_seq'::regclass::oid, '(0,1)'::tid); -- ok
currtid
---------
(0,1)
(1 row)
SELECT currtid2('tid_seq'::text, '(0,1)'::tid); -- ok
currtid2
----------
@ -55,39 +41,25 @@ SELECT currtid2('tid_seq'::text, '(0,1)'::tid); -- ok
DROP SEQUENCE tid_seq;
-- Index, fails with incorrect relation type
CREATE INDEX tid_ind ON tid_tab(a);
SELECT currtid('tid_ind'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: "tid_ind" is an index
SELECT currtid2('tid_ind'::text, '(0,1)'::tid); -- fails
ERROR: "tid_ind" is an index
DROP INDEX tid_ind;
-- Partitioned table, no storage
CREATE TABLE tid_part (a int) PARTITION BY RANGE (a);
SELECT currtid('tid_part'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: cannot look at latest visible tid for relation "public.tid_part"
SELECT currtid2('tid_part'::text, '(0,1)'::tid); -- fails
ERROR: cannot look at latest visible tid for relation "public.tid_part"
DROP TABLE tid_part;
-- Views
-- ctid not defined in the view
CREATE VIEW tid_view_no_ctid AS SELECT a FROM tid_tab;
SELECT currtid('tid_view_no_ctid'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: currtid cannot handle views with no CTID
SELECT currtid2('tid_view_no_ctid'::text, '(0,1)'::tid); -- fails
ERROR: currtid cannot handle views with no CTID
DROP VIEW tid_view_no_ctid;
-- ctid fetched directly from the source table.
CREATE VIEW tid_view_with_ctid AS SELECT ctid, a FROM tid_tab;
SELECT currtid('tid_view_with_ctid'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: tid (0, 1) is not valid for relation "tid_tab"
SELECT currtid2('tid_view_with_ctid'::text, '(0,1)'::tid); -- fails
ERROR: tid (0, 1) is not valid for relation "tid_tab"
INSERT INTO tid_tab VALUES (1);
SELECT currtid('tid_view_with_ctid'::regclass::oid, '(0,1)'::tid); -- ok
currtid
---------
(0,1)
(1 row)
SELECT currtid2('tid_view_with_ctid'::text, '(0,1)'::tid); -- ok
currtid2
----------
@ -98,8 +70,6 @@ DROP VIEW tid_view_with_ctid;
TRUNCATE tid_tab;
-- ctid attribute with incorrect data type
CREATE VIEW tid_view_fake_ctid AS SELECT 1 AS ctid, 2 AS a;
SELECT currtid('tid_view_fake_ctid'::regclass::oid, '(0,1)'::tid); -- fails
ERROR: ctid isn't of type TID
SELECT currtid2('tid_view_fake_ctid'::text, '(0,1)'::tid); -- fails
ERROR: ctid isn't of type TID
DROP VIEW tid_view_fake_ctid;

11
src/test/regress/sql/tid.sql
View File

@ -8,55 +8,46 @@ SELECT min(ctid) FROM tid_tab;
SELECT max(ctid) FROM tid_tab;
TRUNCATE tid_tab;
-- Tests for currtid() and currtid2() with various relation kinds
-- Tests for currtid2() with various relation kinds
-- Materialized view
CREATE MATERIALIZED VIEW tid_matview AS SELECT a FROM tid_tab;
SELECT currtid('tid_matview'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_matview'::text, '(0,1)'::tid); -- fails
INSERT INTO tid_tab VALUES (1);
REFRESH MATERIALIZED VIEW tid_matview;
SELECT currtid('tid_matview'::regclass::oid, '(0,1)'::tid); -- ok
SELECT currtid2('tid_matview'::text, '(0,1)'::tid); -- ok
DROP MATERIALIZED VIEW tid_matview;
TRUNCATE tid_tab;
-- Sequence
CREATE SEQUENCE tid_seq;
SELECT currtid('tid_seq'::regclass::oid, '(0,1)'::tid); -- ok
SELECT currtid2('tid_seq'::text, '(0,1)'::tid); -- ok
DROP SEQUENCE tid_seq;
-- Index, fails with incorrect relation type
CREATE INDEX tid_ind ON tid_tab(a);
SELECT currtid('tid_ind'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_ind'::text, '(0,1)'::tid); -- fails
DROP INDEX tid_ind;
-- Partitioned table, no storage
CREATE TABLE tid_part (a int) PARTITION BY RANGE (a);
SELECT currtid('tid_part'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_part'::text, '(0,1)'::tid); -- fails
DROP TABLE tid_part;
-- Views
-- ctid not defined in the view
CREATE VIEW tid_view_no_ctid AS SELECT a FROM tid_tab;
SELECT currtid('tid_view_no_ctid'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_view_no_ctid'::text, '(0,1)'::tid); -- fails
DROP VIEW tid_view_no_ctid;
-- ctid fetched directly from the source table.
CREATE VIEW tid_view_with_ctid AS SELECT ctid, a FROM tid_tab;
SELECT currtid('tid_view_with_ctid'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_view_with_ctid'::text, '(0,1)'::tid); -- fails
INSERT INTO tid_tab VALUES (1);
SELECT currtid('tid_view_with_ctid'::regclass::oid, '(0,1)'::tid); -- ok
SELECT currtid2('tid_view_with_ctid'::text, '(0,1)'::tid); -- ok
DROP VIEW tid_view_with_ctid;
TRUNCATE tid_tab;
-- ctid attribute with incorrect data type
CREATE VIEW tid_view_fake_ctid AS SELECT 1 AS ctid, 2 AS a;
SELECT currtid('tid_view_fake_ctid'::regclass::oid, '(0,1)'::tid); -- fails
SELECT currtid2('tid_view_fake_ctid'::text, '(0,1)'::tid); -- fails
DROP VIEW tid_view_fake_ctid;