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When creating materialized views, use REFRESH to load data.

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Previously, CREATE MATERIALIZED VIEW ... WITH DATA populated the MV
the same way as CREATE TABLE ... AS.

Instead, reuse the REFRESH logic, which locks down security-restricted
operations and restricts the search_path. This reduces the chance that
a subsequent refresh will fail.

Reported-by: Noah Misch
Backpatch-through: 17
Discussion: https://postgr.es/m/20240630222344.db.nmisch@google.com
This commit is contained in:
Jeff Davis 2024-07-16 15:41:29 -07:00
parent 0a8ca122e5
commit 4b74ebf726
4 changed files with 60 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
src/backend/commands/createas.c
View File

@ -225,10 +225,8 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
Query *query = castNode(Query, stmt->query);
IntoClause *into = stmt->into;
bool is_matview = (into->viewQuery != NULL);
bool do_refresh = false;
DestReceiver *dest;
Oid save_userid = InvalidOid;
int save_sec_context = 0;
int save_nestlevel = 0;
ObjectAddress address;
List *rewritten;
PlannedStmt *plan;
@ -263,18 +261,13 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
Assert(query->commandType == CMD_SELECT);
/*
* For materialized views, lock down security-restricted operations and
* arrange to make GUC variable changes local to this command. This is
* not necessary for security, but this keeps the behavior similar to
* REFRESH MATERIALIZED VIEW. Otherwise, one could create a materialized
* view not possible to refresh.
* For materialized views, always skip data during table creation, and use
* REFRESH instead (see below).
*/
if (is_matview)
{
GetUserIdAndSecContext(&save_userid, &save_sec_context);
SetUserIdAndSecContext(save_userid,
save_sec_context | SECURITY_RESTRICTED_OPERATION);
save_nestlevel = NewGUCNestLevel();
do_refresh = !into->skipData;
into->skipData = true;
}
if (into->skipData)
@ -346,13 +339,18 @@ ExecCreateTableAs(ParseState *pstate, CreateTableAsStmt *stmt,
PopActiveSnapshot();
}
if (is_matview)
/*
* For materialized views, reuse the REFRESH logic, which locks down
* security-restricted operations and restricts the search_path. This
* reduces the chance that a subsequent refresh will fail.
*/
if (do_refresh)
{
/* Roll back any GUC changes */
AtEOXact_GUC(false, save_nestlevel);
RefreshMatViewByOid(address.objectId, false, false,
pstate->p_sourcetext, NULL, qc);
/* Restore userid and security context */
SetUserIdAndSecContext(save_userid, save_sec_context);
if (qc)
qc->commandTag = CMDTAG_SELECT;
}
return address;

64
src/backend/commands/matview.c
View File

@ -112,15 +112,44 @@ SetMatViewPopulatedState(Relation relation, bool newstate)
/*
* ExecRefreshMatView -- execute a REFRESH MATERIALIZED VIEW command
*
* If WITH NO DATA was specified, this is effectively like a TRUNCATE;
* otherwise it is like a TRUNCATE followed by an INSERT using the SELECT
* statement associated with the materialized view. The statement node's
* skipData field shows whether the clause was used.
*/
ObjectAddress
ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
ParamListInfo params, QueryCompletion *qc)
{
Oid matviewOid;
LOCKMODE lockmode;
/* Determine strength of lock needed. */
lockmode = stmt->concurrent ? ExclusiveLock : AccessExclusiveLock;
/*
* Get a lock until end of transaction.
*/
matviewOid = RangeVarGetRelidExtended(stmt->relation,
lockmode, 0,
RangeVarCallbackMaintainsTable,
NULL);
return RefreshMatViewByOid(matviewOid, stmt->skipData, stmt->concurrent,
queryString, params, qc);
}
/*
* RefreshMatViewByOid -- refresh materialized view by OID
*
* This refreshes the materialized view by creating a new table and swapping
* the relfilenumbers of the new table and the old materialized view, so the OID
* of the original materialized view is preserved. Thus we do not lose GRANT
* nor references to this materialized view.
*
* If WITH NO DATA was specified, this is effectively like a TRUNCATE;
* otherwise it is like a TRUNCATE followed by an INSERT using the SELECT
* statement associated with the materialized view. The statement node's
* skipData field shows whether the clause was used.
* If skipData is true, this is effectively like a TRUNCATE; otherwise it is
* like a TRUNCATE followed by an INSERT using the SELECT statement associated
* with the materialized view.
*
* Indexes are rebuilt too, via REINDEX. Since we are effectively bulk-loading
* the new heap, it's better to create the indexes afterwards than to fill them
@ -130,10 +159,10 @@ SetMatViewPopulatedState(Relation relation, bool newstate)
* reflect the result set of the materialized view's query.
*/
ObjectAddress
ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
ParamListInfo params, QueryCompletion *qc)
RefreshMatViewByOid(Oid matviewOid, bool skipData, bool concurrent,
const char *queryString, ParamListInfo params,
QueryCompletion *qc)
{
Oid matviewOid;
Relation matviewRel;
RewriteRule *rule;
List *actions;
@ -143,25 +172,12 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
Oid OIDNewHeap;
DestReceiver *dest;
uint64 processed = 0;
bool concurrent;
LOCKMODE lockmode;
char relpersistence;
Oid save_userid;
int save_sec_context;
int save_nestlevel;
ObjectAddress address;
/* Determine strength of lock needed. */
concurrent = stmt->concurrent;
lockmode = concurrent ? ExclusiveLock : AccessExclusiveLock;
/*
* Get a lock until end of transaction.
*/
matviewOid = RangeVarGetRelidExtended(stmt->relation,
lockmode, 0,
RangeVarCallbackMaintainsTable,
NULL);
matviewRel = table_open(matviewOid, NoLock);
relowner = matviewRel->rd_rel->relowner;
@ -190,7 +206,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
errmsg("CONCURRENTLY cannot be used when the materialized view is not populated")));
/* Check that conflicting options have not been specified. */
if (concurrent && stmt->skipData)
if (concurrent && skipData)
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("%s and %s options cannot be used together",
@ -275,7 +291,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
* Tentatively mark the matview as populated or not (this will roll back
* if we fail later).
*/
SetMatViewPopulatedState(matviewRel, !stmt->skipData);
SetMatViewPopulatedState(matviewRel, !skipData);
/* Concurrent refresh builds new data in temp tablespace, and does diff. */
if (concurrent)
@ -301,7 +317,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
dest = CreateTransientRelDestReceiver(OIDNewHeap);
/* Generate the data, if wanted. */
if (!stmt->skipData)
if (!skipData)
processed = refresh_matview_datafill(dest, dataQuery, queryString);
/* Make the matview match the newly generated data. */
@ -333,7 +349,7 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
* inserts and deletes it issues get counted by lower-level code.)
*/
pgstat_count_truncate(matviewRel);
if (!stmt->skipData)
if (!skipData)
pgstat_count_heap_insert(matviewRel, processed);
}

3
src/include/commands/matview.h
View File

@ -25,6 +25,9 @@ extern void SetMatViewPopulatedState(Relation relation, bool newstate);
extern ObjectAddress ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
ParamListInfo params, QueryCompletion *qc);
extern ObjectAddress RefreshMatViewByOid(Oid matviewOid, bool skipData, bool concurrent,
const char *queryString, ParamListInfo params,
QueryCompletion *qc);
extern DestReceiver *CreateTransientRelDestReceiver(Oid transientoid);

4
src/test/regress/expected/namespace.out
View File

@ -129,8 +129,8 @@ $$;
CREATE TABLE test_maint(i INT);
INSERT INTO test_maint VALUES (1), (2);
CREATE MATERIALIZED VIEW test_maint_mv AS SELECT fn(i) FROM test_maint;
NOTICE: current search_path: test_maint_search_path
NOTICE: current search_path: test_maint_search_path
NOTICE: current search_path: pg_catalog, pg_temp
NOTICE: current search_path: pg_catalog, pg_temp
-- the following commands should see search_path as pg_catalog, pg_temp
CREATE INDEX test_maint_idx ON test_maint_search_path.test_maint (fn(i));
NOTICE: current search_path: pg_catalog, pg_temp