/*
* refresh_matview_datafill
*/
static void
refresh_matview_datafill(DestReceiver *dest, Query *query,
const char *queryString)
{
List *rewritten;
PlannedStmt *plan;
QueryDesc *queryDesc;
Query *copied_query;
/* Lock and rewrite, using a copy to preserve the original query. */
copied_query = copyObject(query);
AcquireRewriteLocks(copied_query, true, false);
rewritten = QueryRewrite(copied_query);
/* SELECT should never rewrite to more or less than one SELECT query */
if (list_length(rewritten) != 1)
elog(ERROR, "unexpected rewrite result for REFRESH MATERIALIZED VIEW");
query = (Query *) linitial(rewritten);
/* Check for user-requested abort. */
CHECK_FOR_INTERRUPTS();
/* Plan the query which will generate data for the refresh. */
plan = pg_plan_query(query, 0, NULL);
/*
* Use a snapshot with an updated command ID to ensure this query sees
* results of any previously executed queries. (This could only matter if
* the planner executed an allegedly-stable function that changed the
* database contents, but let's do it anyway to be safe.)
*/
PushCopiedSnapshot(GetActiveSnapshot());
UpdateActiveSnapshotCommandId();
/* Create a QueryDesc, redirecting output to our tuple receiver */
queryDesc = CreateQueryDesc(plan, queryString,
GetActiveSnapshot(), InvalidSnapshot,
dest, NULL, 0);
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, EXEC_FLAG_WITHOUT_OIDS);
/* run the plan */
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
/* and clean up */
ExecutorFinish(queryDesc);
ExecutorEnd(queryDesc);
FreeQueryDesc(queryDesc);
PopActiveSnapshot();
}
/*
* Implements the 'PREPARE' utility statement.
*/
void
PrepareQuery(PrepareStmt *stmt)
{
const char *commandTag;
Query *query;
List *query_list,
*plan_list;
/*
* Disallow empty-string statement name (conflicts with protocol-level
* unnamed statement).
*/
if (!stmt->name || stmt->name[0] == '\0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_PSTATEMENT_DEFINITION),
errmsg("invalid statement name: must not be empty")));
switch (stmt->query->commandType)
{
case CMD_SELECT:
commandTag = "SELECT";
break;
case CMD_INSERT:
commandTag = "INSERT";
break;
case CMD_UPDATE:
commandTag = "UPDATE";
break;
case CMD_DELETE:
commandTag = "DELETE";
break;
default:
ereport(ERROR,
(errcode(ERRCODE_INVALID_PSTATEMENT_DEFINITION),
errmsg("utility statements cannot be prepared")));
commandTag = NULL; /* keep compiler quiet */
break;
}
/*
* Parse analysis is already done, but we must still rewrite and plan the
* query.
*/
/*
* Because the planner is not cool about not scribbling on its input, we
* make a preliminary copy of the source querytree. This prevents
* problems in the case that the PREPARE is in a portal or plpgsql
* function and is executed repeatedly. (See also the same hack in
* DECLARE CURSOR and EXPLAIN.) XXX the planner really shouldn't modify
* its input ... FIXME someday.
*/
query = copyObject(stmt->query);
/* Rewrite the query. The result could be 0, 1, or many queries. */
AcquireRewriteLocks(query);
query_list = QueryRewrite(query);
/* Generate plans for queries. Snapshot is already set. */
plan_list = pg_plan_queries(query_list, NULL, false);
/*
* Save the results. We don't have the query string for this PREPARE, but
* we do have the string we got from the client, so use that.
*/
StorePreparedStatement(stmt->name,
debug_query_string,
commandTag,
query_list,
plan_list,
stmt->argtype_oids,
true);
}
/*
* refresh_matview_datafill
*/
static void
refresh_matview_datafill(DestReceiver *dest, Query *query,
const char *queryString, Oid relowner)
{
List *rewritten;
PlannedStmt *plan;
QueryDesc *queryDesc;
Oid save_userid;
int save_sec_context;
int save_nestlevel;
Query *copied_query;
/*
* Switch to the owner's userid, so that any functions are run as that
* user. Also lock down security-restricted operations and arrange to
* make GUC variable changes local to this command.
*/
GetUserIdAndSecContext(&save_userid, &save_sec_context);
SetUserIdAndSecContext(relowner,
save_sec_context | SECURITY_RESTRICTED_OPERATION);
save_nestlevel = NewGUCNestLevel();
/* Lock and rewrite, using a copy to preserve the original query. */
copied_query = copyObject(query);
AcquireRewriteLocks(copied_query, true, false);
rewritten = QueryRewrite(copied_query);
/* SELECT should never rewrite to more or less than one SELECT query */
if (list_length(rewritten) != 1)
elog(ERROR, "unexpected rewrite result for REFRESH MATERIALIZED VIEW");
query = (Query *) linitial(rewritten);
/* Check for user-requested abort. */
CHECK_FOR_INTERRUPTS();
/* Plan the query which will generate data for the refresh. */
plan = pg_plan_query(query, 0, NULL);
/*
* Use a snapshot with an updated command ID to ensure this query sees
* results of any previously executed queries. (This could only matter if
* the planner executed an allegedly-stable function that changed the
* database contents, but let's do it anyway to be safe.)
*/
PushCopiedSnapshot(GetActiveSnapshot());
UpdateActiveSnapshotCommandId();
/* Create a QueryDesc, redirecting output to our tuple receiver */
queryDesc = CreateQueryDesc(plan, queryString,
GetActiveSnapshot(), InvalidSnapshot,
dest, NULL, 0);
/* call ExecutorStart to prepare the plan for execution */
ExecutorStart(queryDesc, EXEC_FLAG_WITHOUT_OIDS);
/* run the plan */
ExecutorRun(queryDesc, ForwardScanDirection, 0L);
/* and clean up */
ExecutorFinish(queryDesc);
ExecutorEnd(queryDesc);
FreeQueryDesc(queryDesc);
PopActiveSnapshot();
/* Roll back any GUC changes */
AtEOXact_GUC(false, save_nestlevel);
/* Restore userid and security context */
SetUserIdAndSecContext(save_userid, save_sec_context);
}
