From: Tom Lane Date: Tue, 1 Dec 2020 19:02:28 +0000 (-0500) Subject: Ensure that expandTableLikeClause() re-examines the same table. X-Git-Tag: REL9_5_25~53 X-Git-Url: http://git.postgresql.org/gitweb/?a=commitdiff_plain;h=fb500296dfa6cffdd4dfdc8175e2173c6074f20a;p=postgresql.git 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 502898192 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 --- diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c index db492a7dd1d..9c51b7c04f1 100644 --- a/src/backend/nodes/copyfuncs.c +++ b/src/backend/nodes/copyfuncs.c @@ -2990,6 +2990,7 @@ _copyTableLikeClause(const TableLikeClause *from) COPY_NODE_FIELD(relation); COPY_SCALAR_FIELD(options); + COPY_SCALAR_FIELD(relationOid); return newnode; } diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c index e32b96eb1e2..8d33306f467 100644 --- a/src/backend/nodes/equalfuncs.c +++ b/src/backend/nodes/equalfuncs.c @@ -1149,6 +1149,7 @@ _equalTableLikeClause(const TableLikeClause *a, const TableLikeClause *b) { COMPARE_NODE_FIELD(relation); COMPARE_SCALAR_FIELD(options); + COMPARE_SCALAR_FIELD(relationOid); return true; } diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c index 8d9280197bb..d555c1c8453 100644 --- a/src/backend/nodes/outfuncs.c +++ b/src/backend/nodes/outfuncs.c @@ -2232,6 +2232,7 @@ _outTableLikeClause(StringInfo str, const TableLikeClause *node) WRITE_NODE_FIELD(relation); WRITE_UINT_FIELD(options); + WRITE_OID_FIELD(relationOid); } static void diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index e5c51c5e159..617e577b663 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -3156,6 +3156,7 @@ TableLikeClause: TableLikeClause *n = makeNode(TableLikeClause); n->relation = $2; n->options = $3; + n->relationOid = InvalidOid; $$ = (Node *)n; } ; diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c index 6102a19c3e7..926f0d10fa4 100644 --- a/src/backend/parser/parse_utilcmd.c +++ b/src/backend/parser/parse_utilcmd.c @@ -879,12 +879,16 @@ transformTableLikeClause(CreateStmtContext *cxt, TableLikeClause *table_like_cla * yet know what column numbers the copied columns will have in the * finished table. If any of those options are specified, add the LIKE * clause to cxt->likeclauses so that expandTableLikeClause will be called - * after we do know that. + * after we do know that. Also, remember the relation OID so that + * expandTableLikeClause is certain to open the same table. */ if (table_like_clause->options & (CREATE_TABLE_LIKE_CONSTRAINTS | CREATE_TABLE_LIKE_INDEXES)) + { + table_like_clause->relationOid = RelationGetRelid(relation); cxt->likeclauses = lappend(cxt->likeclauses, table_like_clause); + } /* * Close the parent rel, but keep our AccessShareLock on it until xact @@ -918,9 +922,13 @@ expandTableLikeClause(RangeVar *heapRel, TableLikeClause *table_like_clause) * Open the relation referenced by the LIKE clause. We should still have * the table lock obtained by transformTableLikeClause (and this'll throw * an assertion failure if not). Hence, no need to recheck privileges - * etc. + * etc. We must open the rel by OID not name, to be sure we get the same + * table. */ - relation = relation_openrv(table_like_clause->relation, NoLock); + if (!OidIsValid(table_like_clause->relationOid)) + elog(ERROR, "expandTableLikeClause called on untransformed LIKE clause"); + + relation = relation_open(table_like_clause->relationOid, NoLock); tupleDesc = RelationGetDescr(relation); constr = tupleDesc->constr; diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 03865e71651..da70448409b 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -604,6 +604,7 @@ typedef struct TableLikeClause NodeTag type; RangeVar *relation; bits32 options; /* OR of TableLikeOption flags */ + Oid relationOid; /* If table has been looked up, its OID */ } TableLikeClause; typedef enum TableLikeOption diff --git a/src/test/regress/expected/create_table_like.out b/src/test/regress/expected/create_table_like.out index c72591ee159..60dc9499ebd 100644 --- a/src/test/regress/expected/create_table_like.out +++ b/src/test/regress/expected/create_table_like.out @@ -275,6 +275,25 @@ Check constraints: "ctlt1_a_check" CHECK (length(a) > 2) DROP TABLE public.pg_attrdef; +-- Check that LIKE isn't confused when new table masks the old, either +BEGIN; +CREATE SCHEMA ctl_schema; +SET LOCAL search_path = ctl_schema, public; +CREATE TABLE ctlt1 (LIKE ctlt1 INCLUDING ALL); +\d+ ctlt1 + Table "ctl_schema.ctlt1" + Column | Type | Modifiers | Storage | Stats target | Description +--------+------+-----------+----------+--------------+------------- + a | text | not null | main | | A + b | text | | extended | | B +Indexes: + "ctlt1_pkey" PRIMARY KEY, btree (a) + "ctlt1_b_idx" btree (b) + "ctlt1_expr_idx" btree ((a || b)) +Check constraints: + "ctlt1_a_check" CHECK (length(a) > 2) + +ROLLBACK; DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE; NOTICE: drop cascades to table inhe /* LIKE with other relation kinds */ diff --git a/src/test/regress/sql/create_table_like.sql b/src/test/regress/sql/create_table_like.sql index a7d4a669f5f..ad5d4e3e3a4 100644 --- a/src/test/regress/sql/create_table_like.sql +++ b/src/test/regress/sql/create_table_like.sql @@ -122,6 +122,14 @@ CREATE TABLE pg_attrdef (LIKE ctlt1 INCLUDING ALL); \d+ public.pg_attrdef DROP TABLE public.pg_attrdef; +-- Check that LIKE isn't confused when new table masks the old, either +BEGIN; +CREATE SCHEMA ctl_schema; +SET LOCAL search_path = ctl_schema, public; +CREATE TABLE ctlt1 (LIKE ctlt1 INCLUDING ALL); +\d+ ctlt1 +ROLLBACK; + DROP TABLE ctlt1, ctlt2, ctlt3, ctlt4, ctlt12_storage, ctlt12_comments, ctlt1_inh, ctlt13_inh, ctlt13_like, ctlt_all, ctla, ctlb CASCADE;