Function execute_sql_string

src/backend/commands/extension.c:714–813

* Execute given SQL string. * * Note: it's tempting to just use SPI to execute the string, but that does * not work very well. The really serious problem is that SPI will parse, * analyze, and plan the whole string before executing any of it; of course * this fails if there are any plannable statements referring to objects * created earlier in the script. A lesser annoyance is that SPI ins

 * could be very long.
 */
void
execute_sql_string(const char *sql)
{
	List	   *raw_parsetree_list;
	DestReceiver *dest;
	ListCell   *lc1;

	/*
	 * Parse the SQL string into a list of raw parse trees.
	 */
	raw_parsetree_list = pg_parse_query(sql);

	/* All output from SELECTs goes to the bit bucket */
	dest = CreateDestReceiver(DestNone);

	/*
	 * Do parse analysis, rule rewrite, planning, and execution for each raw
	 * parsetree.  We must fully execute each query before beginning parse
	 * analysis on the next one, since there may be interdependencies.
	 */
	foreach(lc1, raw_parsetree_list)
	{
		RawStmt    *parsetree = lfirst_node(RawStmt, lc1);
		MemoryContext per_parsetree_context,
					oldcontext;
		List	   *stmt_list;
		ListCell   *lc2;

		/*
		 * We do the work for each parsetree in a short-lived context, to
		 * limit the memory used when there are many commands in the string.
		 */
		per_parsetree_context =
			AllocSetContextCreate(CurrentMemoryContext,
								  "execute_sql_string per-statement context",
								  ALLOCSET_DEFAULT_SIZES);
		oldcontext = MemoryContextSwitchTo(per_parsetree_context);

		/* Be sure parser can see any DDL done so far */
		CommandCounterIncrement();

		stmt_list = pg_analyze_and_rewrite(parsetree,
										   sql,
										   NULL,
										   0,
										   NULL);
		stmt_list = pg_plan_queries(stmt_list, sql, CURSOR_OPT_PARALLEL_OK, NULL);

		foreach(lc2, stmt_list)
		{
			PlannedStmt *stmt = lfirst_node(PlannedStmt, lc2);

			CommandCounterIncrement();

			PushActiveSnapshot(GetTransactionSnapshot());

			if (stmt->utilityStmt == NULL)
			{