diff --git a/src/pl/plpgsql/src/expected/plpgsql_simple.out b/src/pl/plpgsql/src/expected/plpgsql_simple.out index e1f5d670fb..7b22e60f19 100644 --- a/src/pl/plpgsql/src/expected/plpgsql_simple.out +++ b/src/pl/plpgsql/src/expected/plpgsql_simple.out @@ -89,3 +89,32 @@ select simplecaller(); 4 (1 row) +-- Check case where called function changes from non-SRF to SRF (bug #18497) +create or replace function simplecaller() returns int language plpgsql +as $$ +declare x int; +begin + x := simplesql(); + return x; +end$$; +select simplecaller(); + simplecaller +-------------- + 4 +(1 row) + +drop function simplesql(); +create function simplesql() returns setof int language sql +as $$select 22 + 22$$; +select simplecaller(); + simplecaller +-------------- + 44 +(1 row) + +select simplecaller(); + simplecaller +-------------- + 44 +(1 row) + diff --git a/src/pl/plpgsql/src/pl_exec.c b/src/pl/plpgsql/src/pl_exec.c index 4b326932a7..d486b70369 100644 --- a/src/pl/plpgsql/src/pl_exec.c +++ b/src/pl/plpgsql/src/pl_exec.c @@ -339,6 +339,7 @@ static void exec_eval_cleanup(PLpgSQL_execstate *estate); static void exec_prepare_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr, int cursorOptions); static void exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr); +static bool exec_is_simple_query(PLpgSQL_expr *expr); static void exec_save_simple_expr(PLpgSQL_expr *expr, CachedPlan *cplan); static void exec_check_rw_parameter(PLpgSQL_expr *expr); static bool exec_eval_simple_expr(PLpgSQL_execstate *estate, @@ -6036,12 +6037,18 @@ exec_eval_simple_expr(PLpgSQL_execstate *estate, * release it, so we don't leak plans intra-transaction. */ if (expr->expr_simple_plan_lxid == curlxid) - { ReleaseCachedPlan(expr->expr_simple_plan, estate->simple_eval_resowner); - expr->expr_simple_plan = NULL; - expr->expr_simple_plan_lxid = InvalidLocalTransactionId; - } + + /* + * Reset to "not simple" to leave sane state (with no dangling + * pointers) in case we fail while replanning. expr_simple_plansource + * can be left alone however, as that cannot move. + */ + expr->expr_simple_expr = NULL; + expr->expr_rw_param = NULL; + expr->expr_simple_plan = NULL; + expr->expr_simple_plan_lxid = InvalidLocalTransactionId; /* Do the replanning work in the eval_mcontext */ oldcontext = MemoryContextSwitchTo(get_eval_mcontext(estate)); @@ -6057,11 +6064,15 @@ exec_eval_simple_expr(PLpgSQL_execstate *estate, Assert(cplan != NULL); /* - * This test probably can't fail either, but if it does, cope by - * declaring the plan to be non-simple. On success, we'll acquire a - * refcount on the new plan, stored in simple_eval_resowner. + * Recheck exec_is_simple_query, which could now report false in + * edge-case scenarios such as a non-SRF having been replaced with a + * SRF. Also recheck CachedPlanAllowsSimpleValidityCheck, just to be + * sure. If either test fails, cope by declaring the plan to be + * non-simple. On success, we'll acquire a refcount on the new plan, + * stored in simple_eval_resowner. */ - if (CachedPlanAllowsSimpleValidityCheck(expr->expr_simple_plansource, + if (exec_is_simple_query(expr) && + CachedPlanAllowsSimpleValidityCheck(expr->expr_simple_plansource, cplan, estate->simple_eval_resowner)) { @@ -6073,9 +6084,6 @@ exec_eval_simple_expr(PLpgSQL_execstate *estate, { /* Release SPI_plan_get_cached_plan's refcount */ ReleaseCachedPlan(cplan, CurrentResourceOwner); - /* Mark expression as non-simple, and fail */ - expr->expr_simple_expr = NULL; - expr->expr_rw_param = NULL; return false; } @@ -7919,7 +7927,6 @@ exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr) { List *plansources; CachedPlanSource *plansource; - Query *query; CachedPlan *cplan; MemoryContext oldcontext; @@ -7935,65 +7942,14 @@ exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr) * called immediately after creating the CachedPlanSource, we need not * worry about the query being stale. */ - - /* - * We can only test queries that resulted in exactly one CachedPlanSource - */ - plansources = SPI_plan_get_plan_sources(expr->plan); - if (list_length(plansources) != 1) + if (!exec_is_simple_query(expr)) return; + + /* exec_is_simple_query verified that there's just one CachedPlanSource */ + plansources = SPI_plan_get_plan_sources(expr->plan); plansource = (CachedPlanSource *) linitial(plansources); /* - * 1. There must be one single querytree. - */ - if (list_length(plansource->query_list) != 1) - return; - query = (Query *) linitial(plansource->query_list); - - /* - * 2. It must be a plain SELECT query without any input tables - */ - if (!IsA(query, Query)) - return; - if (query->commandType != CMD_SELECT) - return; - if (query->rtable != NIL) - return; - - /* - * 3. Can't have any subplans, aggregates, qual clauses either. (These - * tests should generally match what inline_function() checks before - * inlining a SQL function; otherwise, inlining could change our - * conclusion about whether an expression is simple, which we don't want.) - */ - if (query->hasAggs || - query->hasWindowFuncs || - query->hasTargetSRFs || - query->hasSubLinks || - query->cteList || - query->jointree->fromlist || - query->jointree->quals || - query->groupClause || - query->groupingSets || - query->havingQual || - query->windowClause || - query->distinctClause || - query->sortClause || - query->limitOffset || - query->limitCount || - query->setOperations) - return; - - /* - * 4. The query must have a single attribute as result - */ - if (list_length(query->targetList) != 1) - return; - - /* - * OK, we can treat it as a simple plan. - * * Get the generic plan for the query. If replanning is needed, do that * work in the eval_mcontext. (Note that replanning could throw an error, * in which case the expr is left marked "not simple", which is fine.) @@ -8030,6 +7986,81 @@ exec_simple_check_plan(PLpgSQL_execstate *estate, PLpgSQL_expr *expr) ReleaseCachedPlan(cplan, CurrentResourceOwner); } +/* + * exec_is_simple_query - precheck a query tree to see if it might be simple + * + * Check the analyzed-and-rewritten form of a query to see if we will be + * able to treat it as a simple expression. It is caller's responsibility + * that the CachedPlanSource be up-to-date. + */ +static bool +exec_is_simple_query(PLpgSQL_expr *expr) +{ + List *plansources; + CachedPlanSource *plansource; + Query *query; + + /* + * We can only test queries that resulted in exactly one CachedPlanSource. + */ + plansources = SPI_plan_get_plan_sources(expr->plan); + if (list_length(plansources) != 1) + return false; + plansource = (CachedPlanSource *) linitial(plansources); + + /* + * 1. There must be one single querytree. + */ + if (list_length(plansource->query_list) != 1) + return false; + query = (Query *) linitial(plansource->query_list); + + /* + * 2. It must be a plain SELECT query without any input tables. + */ + if (!IsA(query, Query)) + return false; + if (query->commandType != CMD_SELECT) + return false; + if (query->rtable != NIL) + return false; + + /* + * 3. Can't have any subplans, aggregates, qual clauses either. (These + * tests should generally match what inline_function() checks before + * inlining a SQL function; otherwise, inlining could change our + * conclusion about whether an expression is simple, which we don't want.) + */ + if (query->hasAggs || + query->hasWindowFuncs || + query->hasTargetSRFs || + query->hasSubLinks || + query->cteList || + query->jointree->fromlist || + query->jointree->quals || + query->groupClause || + query->groupingSets || + query->havingQual || + query->windowClause || + query->distinctClause || + query->sortClause || + query->limitOffset || + query->limitCount || + query->setOperations) + return false; + + /* + * 4. The query must have a single attribute as result. + */ + if (list_length(query->targetList) != 1) + return false; + + /* + * OK, we can treat it as a simple plan. + */ + return true; +} + /* * exec_save_simple_expr --- extract simple expression from CachedPlan */ diff --git a/src/pl/plpgsql/src/sql/plpgsql_simple.sql b/src/pl/plpgsql/src/sql/plpgsql_simple.sql index 57020d22d6..143bf09dce 100644 --- a/src/pl/plpgsql/src/sql/plpgsql_simple.sql +++ b/src/pl/plpgsql/src/sql/plpgsql_simple.sql @@ -80,3 +80,25 @@ create or replace function simplesql() returns int language sql as $$select 2 + 2$$; select simplecaller(); + + +-- Check case where called function changes from non-SRF to SRF (bug #18497) + +create or replace function simplecaller() returns int language plpgsql +as $$ +declare x int; +begin + x := simplesql(); + return x; +end$$; + +select simplecaller(); + +drop function simplesql(); + +create function simplesql() returns setof int language sql +as $$select 22 + 22$$; + +select simplecaller(); + +select simplecaller();