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Commit f00c440

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Ensure that expandTableLikeClause() re-examines the same table.
As it stood, expandTableLikeClause() re-did the same relation_openrv call that transformTableLikeClause() had done. However there are scenarios where this would not find the same table as expected. We hold lock on the LIKE source table, so it can't be renamed or dropped, but another table could appear before it in the search path. This explains the odd behavior reported in bug #16758 when cloning a table as a temp table of the same name. This case worked as expected before commit 5028981 introduced the need to open the source table twice, so we should fix it. To make really sure we get the same table, let's re-open it by OID not name. That requires adding an OID field to struct TableLikeClause, which is a little nervous-making from an ABI standpoint, but as long as it's at the end I don't think there's any serious risk. Per bug #16758 from Marc Boeren. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16758-840e84a6cfab276d@postgresql.org
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‎src/backend/nodes/copyfuncs.c‎

Copy file name to clipboardExpand all lines: src/backend/nodes/copyfuncs.c
+1Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3025,6 +3025,7 @@ _copyTableLikeClause(const TableLikeClause *from)
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COPY_NODE_FIELD(relation);
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COPY_SCALAR_FIELD(options);
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COPY_SCALAR_FIELD(relationOid);
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return newnode;
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}
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‎src/backend/nodes/equalfuncs.c‎

Copy file name to clipboardExpand all lines: src/backend/nodes/equalfuncs.c
+1Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1172,6 +1172,7 @@ _equalTableLikeClause(const TableLikeClause *a, const TableLikeClause *b)
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{
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COMPARE_NODE_FIELD(relation);
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COMPARE_SCALAR_FIELD(options);
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COMPARE_SCALAR_FIELD(relationOid);
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return true;
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}
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‎src/backend/nodes/outfuncs.c‎

Copy file name to clipboardExpand all lines: src/backend/nodes/outfuncs.c
+1Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2541,6 +2541,7 @@ _outTableLikeClause(StringInfo str, const TableLikeClause *node)
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WRITE_NODE_FIELD(relation);
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WRITE_UINT_FIELD(options);
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WRITE_OID_FIELD(relationOid);
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}
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static void
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‎src/backend/parser/gram.y‎

Copy file name to clipboardExpand all lines: src/backend/parser/gram.y
+1Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -3174,6 +3174,7 @@ TableLikeClause:
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TableLikeClause *n = makeNode(TableLikeClause);
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n->relation = $2;
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n->options = $3;
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n->relationOid = InvalidOid;
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$$ = (Node *)n;
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}
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;
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‎src/backend/parser/parse_utilcmd.c‎

Copy file name to clipboardExpand all lines: src/backend/parser/parse_utilcmd.c
+11-3Lines changed: 11 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -909,12 +909,16 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla
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* yet know what column numbers the copied columns will have in the
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* finished table. If any of those options are specified, add the LIKE
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* clause to cxt->likeclauses so that expandTableLikeClause will be called
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* after we do know that.
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* after we do know that. Also, remember the relation OID so that
913+
* expandTableLikeClause is certain to open the same table.
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*/
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if (table_like_clause->options &
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(CREATE_TABLE_LIKE_CONSTRAINTS |
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CREATE_TABLE_LIKE_INDEXES))
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{
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table_like_clause->relationOid = RelationGetRelid(relation);
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cxt->likeclauses = lappend(cxt->likeclauses, table_like_clause);
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}
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/*
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* Close the parent rel, but keep our AccessShareLock on it until xact
@@ -948,9 +952,13 @@ expandTableLikeClause(RangeVar *heapRel, TableLikeClause *table_like_clause)
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* Open the relation referenced by the LIKE clause. We should still have
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* the table lock obtained by transformTableLikeClause (and this'll throw
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* an assertion failure if not). Hence, no need to recheck privileges
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* etc.
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* etc. We must open the rel by OID not name, to be sure we get the same
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* table.
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*/
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relation = relation_openrv(table_like_clause->relation, NoLock);
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if (!OidIsValid(table_like_clause->relationOid))
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elog(ERROR, "expandTableLikeClause called on untransformed LIKE clause");
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relation = relation_open(table_like_clause->relationOid, NoLock);
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tupleDesc = RelationGetDescr(relation);
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constr = tupleDesc->constr;
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‎src/include/nodes/parsenodes.h‎

Copy file name to clipboardExpand all lines: src/include/nodes/parsenodes.h
+1Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -610,6 +610,7 @@ typedef struct TableLikeClause
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NodeTag type;
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RangeVar *relation;
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bits32 options; /* OR of TableLikeOption flags */
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Oid relationOid; /* If table has been looked up, its OID */
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} TableLikeClause;
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typedef enum TableLikeOption
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‎src/test/regress/expected/create_table_like.out‎

Copy file name to clipboardExpand all lines: src/test/regress/expected/create_table_like.out
+19Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -275,6 +275,25 @@ Check constraints:
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"ctlt1_a_check" CHECK (length(a) > 2)
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DROP TABLE public.pg_attrdef;
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-- Check that LIKE isn't confused when new table masks the old, either
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BEGIN;
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CREATE SCHEMA ctl_schema;
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SET LOCAL search_path = ctl_schema, public;
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CREATE TABLE ctlt1 (LIKE ctlt1 INCLUDING ALL);
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\d+ ctlt1
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Table "ctl_schema.ctlt1"
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Column | Type | Modifiers | Storage | Stats target | Description
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--------+------+-----------+----------+--------------+-------------
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a | text | not null | main | | A
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b | text | | extended | | B
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Indexes:
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"ctlt1_pkey" PRIMARY KEY, btree (a)
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"ctlt1_b_idx" btree (b)
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"ctlt1_expr_idx" btree ((a || b))
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Check constraints:
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"ctlt1_a_check" CHECK (length(a) > 2)
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ROLLBACK;
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DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE;
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NOTICE: drop cascades to table inhe
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/* LIKE with other relation kinds */
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‎src/test/regress/sql/create_table_like.sql‎

Copy file name to clipboardExpand all lines: src/test/regress/sql/create_table_like.sql
+8Lines changed: 8 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -122,6 +122,14 @@ CREATE TABLE pg_attrdef (LIKE ctlt1 INCLUDING ALL);
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\d+ public.pg_attrdef
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DROP TABLE public.pg_attrdef;
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-- Check that LIKE isn't confused when new table masks the old, either
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BEGIN;
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CREATE SCHEMA ctl_schema;
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SET LOCAL search_path = ctl_schema, public;
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CREATE TABLE ctlt1 (LIKE ctlt1 INCLUDING ALL);
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\d+ ctlt1
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ROLLBACK;
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DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE;
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