plpgsql_check ============= I founded this project, because I wanted to publish the code I wrote in the last two years, when I tried to write enhanced checking for PostgreSQL upstream. It was not fully successful - integration into upstream requires some larger plpgsql refactoring - probably it will not be done in next years (now is Dec 2013). But written code is fully functional and can be used in production (and it is used in production). So, I created this extension to be available for all plpgsql developers. If you like it and if you would to join to development of this extension, register yourself to [postgresql extension hacking](https://groups.google.com/forum/#!forum/postgresql-extensions-hacking) google group. # Features * check fields of referenced database objects and types inside embedded SQL * using correct types of function parameters * unused variables and function argumens, unmodified OUT argumens * partially detection of dead code (due RETURN command) * detection of missing RETURN command in function * try to identify unwanted hidden casts, that can be performance issue like unused indexes * possibility to collect relations and functions used by function I invite any ideas, patches, bugreports plpgsql_check is next generation of plpgsql_lint. It allows to check source code by explicit call plpgsql_check_function. PostgreSQL PostgreSQL 9.4, 9.5, 9.6, 10, 11 are supported (Develop 12 is supported too). The SQL statements inside PL/pgSQL functions are checked by validator for semantic errors. These errors can be found by plpgsql_check_function: # Active mode postgres=# load 'plpgsql'; -- 1.1 and higher doesn't need it LOAD postgres=# CREATE EXTENSION plpgsql_check; LOAD postgres=# CREATE TABLE t1(a int, b int); CREATE TABLE postgres=# CREATE OR REPLACE FUNCTION public.f1() RETURNS void LANGUAGE plpgsql AS $function$ DECLARE r record; BEGIN FOR r IN SELECT * FROM t1 LOOP RAISE NOTICE '%', r.c; -- there is bug - table t1 missing "c" column END LOOP; END; $function$; CREATE FUNCTION postgres=# select f1(); -- execution doesn't find a bug due to empty table t1 f1 ──── (1 row) postgres=# \x Expanded display is on. postgres=# select * from plpgsql_check_function_tb('f1()'); ─[ RECORD 1 ]─────────────────────────── functionid │ f1 lineno │ 6 statement │ RAISE sqlstate │ 42703 message │ record "r" has no field "c" detail │ [null] hint │ [null] level │ error position │ 0 query │ [null] postgres=# \sf+ f1 CREATE OR REPLACE FUNCTION public.f1() RETURNS void LANGUAGE plpgsql 1 AS $function$ 2 DECLARE r record; 3 BEGIN 4 FOR r IN SELECT * FROM t1 5 LOOP 6 RAISE NOTICE '%', r.c; -- there is bug - table t1 missing "c" column 7 END LOOP; 8 END; 9 $function$ Function plpgsql_check_function() has two possible formats: text or xml select * from plpgsql_check_function('f1()', fatal_errors := false); plpgsql_check_function ------------------------------------------------------------------------ error:42703:4:SQL statement:column "c" of relation "t1" does not exist Query: update t1 set c = 30 -- ^ error:42P01:7:RAISE:missing FROM-clause entry for table "r" Query: SELECT r.c -- ^ error:42601:7:RAISE:too few parameters specified for RAISE (7 rows) postgres=# select * from plpgsql_check_function('fx()', format:='xml'); plpgsql_check_function ──────────────────────────────────────────────────────────────── ↵ ↵ error ↵ 42P01 ↵ relation "foo111" does not exist ↵ RETURN ↵ SELECT (select a from foo111)↵ ↵ (1 row) ## Arguments You can set level of warnings via function's parameters: ### Mandatory arguments * function name or function signature - these functions requires function specification. Any function in PostgreSQL can be specified by Oid or by name or by signature. When you know oid or complete function's signature, you can use a regprocedure type parameter like `'fx()'::regprocedure` or `16799::regprocedure`. Possible alternative is using a name only, when function's name is unique - like `'fx'`. When the name is not unique or the function doesn't exists it raises a error. ### Optional arguments * `fatal_errors boolean DEFAULT true` - stop on first error * `other_warnings boolean DEFAULT true` - show warnings like different attributes number in assignmenet on left and right side, variable overlaps function's parameter, unused variables, unwanted casting, .. * `extra_warnings boolean DEFAULT true` - show warnings like missing `RETURN`, shadowed variables, dead code, never read (unused) function's parameter, unmodified variables, .. * `performance_warnings boolean DEFAULT false` - performance related warnings like declared type with type modificator, casting, implicit casts in where clause (can be reason why index is not used), .. ## Triggers When you want to check any trigger, you have to enter a relation that will be used together with trigger function CREATE TABLE bar(a int, b int); postgres=# \sf+ foo_trg CREATE OR REPLACE FUNCTION public.foo_trg() RETURNS trigger LANGUAGE plpgsql 1 AS $function$ 2 BEGIN 3 NEW.c := NEW.a + NEW.b; 4 RETURN NEW; 5 END; 6 $function$ Missing relation specification postgres=# select * from plpgsql_check_function('foo_trg()'); ERROR: missing trigger relation HINT: Trigger relation oid must be valid Correct trigger checking (with specified relation) postgres=# select * from plpgsql_check_function('foo_trg()', 'bar'); plpgsql_check_function -------------------------------------------------------- error:42703:3:assignment:record "new" has no field "c" (1 row) ## Mass check You can use the plpgsql_check_function for mass check functions and mass check triggers. Please, test following queries: -- check all nontrigger plpgsql functions SELECT p.oid, p.proname, plpgsql_check_function(p.oid) FROM pg_catalog.pg_namespace n JOIN pg_catalog.pg_proc p ON pronamespace = n.oid JOIN pg_catalog.pg_language l ON p.prolang = l.oid WHERE l.lanname = 'plpgsql' AND p.prorettype <> 2279; or SELECT p.proname, tgrelid::regclass, cf.* FROM pg_proc p JOIN pg_trigger t ON t.tgfoid = p.oid JOIN pg_language l ON p.prolang = l.oid JOIN pg_namespace n ON p.pronamespace = n.oid, LATERAL plpgsql_check_function(p.oid, t.tgrelid) cf WHERE n.nspname = 'public' and l.lanname = 'plpgsql' or -- check all plpgsql functions (functions or trigger functions with defined triggers) SELECT (pcf).functionid::regprocedure, (pcf).lineno, (pcf).statement, (pcf).sqlstate, (pcf).message, (pcf).detail, (pcf).hint, (pcf).level, (pcf)."position", (pcf).query, (pcf).context FROM ( SELECT plpgsql_check_function_tb(pg_proc.oid, COALESCE(pg_trigger.tgrelid, 0)) AS pcf FROM pg_proc LEFT JOIN pg_trigger ON (pg_trigger.tgfoid = pg_proc.oid) WHERE prolang = (SELECT lang.oid FROM pg_language lang WHERE lang.lanname = 'plpgsql') AND pronamespace <> (SELECT nsp.oid FROM pg_namespace nsp WHERE nsp.nspname = 'pg_catalog') AND -- ignore unused triggers (pg_proc.prorettype <> (SELECT typ.oid FROM pg_type typ WHERE typ.typname = 'trigger') OR pg_trigger.tgfoid IS NOT NULL) OFFSET 0 ) ss ORDER BY (pcf).functionid::regprocedure::text, (pcf).lineno # Passive mode Functions should be checked on start - plpgsql_check module must be loaded. ## Configuration plpgsql_check.mode = [ disabled | by_function | fresh_start | every_start ] plpgsql_check.fatal_errors = [ yes | no ] plpgsql_check.show_nonperformance_warnings = false plpgsql_check.show_performance_warnings = false Default mode is by_function, that means that the enhanced check is done only in active mode - by plpgsql_check_function. You can enable passive mode by load 'plpgsql'; -- 1.1 and higher doesn't need it load 'plpgsql_check'; set plpgsql_check.mode = 'every_start'; SELECT fx(10); -- run functions - function is checked before runtime starts it # Limits plpgsql_check should find almost all errors on really static code. When developer use some PLpgSQL's dynamic features like dynamic SQL or record data type, then false positives are possible. These should be rare - in well written code - and then the affected function should be redesigned or plpgsql_check should be disabled for this function. CREATE OR REPLACE FUNCTION f1() RETURNS void AS $$ DECLARE r record; BEGIN FOR r IN EXECUTE 'SELECT * FROM t1' LOOP RAISE NOTICE '%', r.c; END LOOP; END; $$ LANGUAGE plpgsql SET plpgsql.enable_check TO false; A usage of plpgsql_check adds a small overhead (in enabled passive mode) and you should use it only in develop or preprod environments. ## Dynamic SQL This module doesn't check queries that are assembled in runtime. It is not possible to identify results of dynamic queries - so plpgsql_check cannot to set correct type to record variables and cannot to check a dependent SQLs and expressions. Don't use record variable as target for dynamic queries or disable plpgsql_check for functions that use dynamic queries. ## Refcursors plpgsql_check should not to detect structure of referenced cursors. A reference on cursor in PLpgSQL is implemented as name of global cursor. In check time, the name is not known (not in all possibilities), and global cursor doesn't exist. It is significant break for any static analyse. PLpgSQL cannot to set correct type for record variables and cannot to check a dependent SQLs and expressions. A solution is same like dynamic SQL. Don't use record variable as target when you use refcursor type or disable plpgsql_check for these functions. CREATE OR REPLACE FUNCTION foo(refcur_var refcursor) RETURNS void AS $$ DECLARE rec_var record; BEGIN FETCH refcur_var INTO rec_var; -- this is STOP for plpgsql_check RAISE NOTICE '%', rec_var; -- record rec_var is not assigned yet error In this case a record type should not be used (use known rowtype instead): CREATE OR REPLACE FUNCTION foo(refcur_var refcursor) RETURNS void AS $$ DECLARE rec_var some_rowtype; BEGIN FETCH refcur_var INTO rec_var; RAISE NOTICE '%', rec_var; ## Temporary tables plpgsql_check cannot verify queries over temporary tables that are created in plpgsql's function runtime. For this use case it is necessary to create a fake temp table or disable plpgsql_check for this function. In reality temp tables are stored in own (per user) schema with higher priority than persistent tables. So you can do (with following trick safetly): CREATE OR REPLACE FUNCTION public.disable_dml() RETURNS trigger LANGUAGE plpgsql AS $function$ BEGIN RAISE EXCEPTION SQLSTATE '42P01' USING message = format('this instance of %I table doesn''t allow any DML operation', TG_TABLE_NAME), hint = format('you should to run "CREATE TEMP TABLE %1$I(LIKE %1$I INCLUDING ALL);" statement', TG_TABLE_NAME); RETURN NULL; END; $function$; CREATE TABLE foo(a int, b int); -- doesn't hold data ever CREATE TRIGGER foo_disable_dml BEFORE INSERT OR UPDATE OR DELETE ON foo EXECUTE PROCEDURE disable_dml(); postgres=# INSERT INTO foo VALUES(10,20); ERROR: this instance of foo table doesn't allow any DML operation HINT: you should to run "CREATE TEMP TABLE foo(LIKE foo INCLUDING ALL);" statement postgres=# CREATE TABLE postgres=# INSERT INTO foo VALUES(10,20); INSERT 0 1 This trick emulates GLOBAL TEMP tables partially and it allows a statical validation. Other possibility is using a [template foreign data wrapper] (https://github.com/okbob/template_fdw) # Dependency list A function plpgsql_show_dependency_tb can show all functions and relations used inside processed function: postgres=# select * from plpgsql_show_dependency_tb('testfunc(int,float)'); ┌──────────┬───────┬────────┬─────────┬────────────────────────────┐ │ type │ oid │ schema │ name │ params │ ╞══════════╪═══════╪════════╪═════════╪════════════════════════════╡ │ FUNCTION │ 36008 │ public │ myfunc1 │ (integer,double precision) │ │ FUNCTION │ 35999 │ public │ myfunc2 │ (integer,double precision) │ │ RELATION │ 36005 │ public │ myview │ │ │ RELATION │ 36002 │ public │ mytable │ │ └──────────┴───────┴────────┴─────────┴────────────────────────────┘ (4 rows) # Profiler The plpgsql_check contains simple profiler of plpgsql functions and procedures. It can work with/without a access to shared memory. It depends on `shared_preload_libraries` config. When plpgsql_check was initialized by `shared_preload_libraries`, then it can allocate shared memory, and function's profiles are stored there. When plpgsql_check cannot to allocate shared momory, the profile is stored in session memory. The profile of any function is updated after successful execution of function. When function was canceled or it fails, the profiles is not updated. Due dependencies, `shared_preload_libraries` should to contains `plpgsql` first postgres=# show shared_preload_libraries ; ┌──────────────────────────┐ │ shared_preload_libraries │ ╞══════════════════════════╡ │ plpgsql,plpgsql_check │ └──────────────────────────┘ (1 row) The profiler is active when GUC `plpgsql_check.profiler` is on. The profiler doesn't require shared memory, but if there are not shared memory, then the profile is limmitted just to active session. Attention: A update of shared profiles can decrease performance on servers under higher load. The profile can be displayed by function `plpgsql_profiler_function_tb`: postgres=# select lineno, avg_time, source from plpgsql_profiler_function_tb('fx(int)'); ┌────────┬──────────┬───────────────────────────────────────────────────────────────────┐ │ lineno │ avg_time │ source │ ╞════════╪══════════╪═══════════════════════════════════════════════════════════════════╡ │ 1 │ │ │ │ 2 │ │ declare result int = 0; │ │ 3 │ 0.075 │ begin │ │ 4 │ 0.202 │ for i in 1..$1 loop │ │ 5 │ 0.005 │ select result + i into result; select result + i into result; │ │ 6 │ │ end loop; │ │ 7 │ 0 │ return result; │ │ 8 │ │ end; │ └────────┴──────────┴───────────────────────────────────────────────────────────────────┘ (9 rows) There are two functions for cleaning stored profiles: `plpgsql_profiler_reset_all()` and `plpgsql_profiler_reset(regprocedure)`. ## Note There is another very good PLpgSQL profiler - https://bitbucket.org/openscg/plprofiler My extension is designed to be simple for use and practical. Nothing more or less. plprofiler is more complex. It build call graphs and from this graph it can creates flame graph of execution times. Both extensions can be used together with buildin PostgreSQL's feature - tracking functions. set track_functions to 'pl'; ... select * from pg_stat_user_functions; # Compilation You need a development environment for PostgreSQL extensions: make clean make install result: [pavel@localhost plpgsql_check]$ make USE_PGXS=1 clean rm -f plpgsql_check.so libplpgsql_check.a libplpgsql_check.pc rm -f plpgsql_check.o rm -rf results/ regression.diffs regression.out tmp_check/ log/ [pavel@localhost plpgsql_check]$ make USE_PGXS=1 clean rm -f plpgsql_check.so libplpgsql_check.a libplpgsql_check.pc rm -f plpgsql_check.o rm -rf results/ regression.diffs regression.out tmp_check/ log/ [pavel@localhost plpgsql_check]$ make USE_PGXS=1 all clang -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fpic -I/usr/local/pgsql/lib/pgxs/src/makefiles/../../src/pl/plpgsql/src -I. -I./ -I/usr/local/pgsql/include/server -I/usr/local/pgsql/include/internal -D_GNU_SOURCE -c -o plpgsql_check.o plpgsql_check.c clang -O2 -Wall -Wmissing-prototypes -Wpointer-arith -Wdeclaration-after-statement -Wendif-labels -Wmissing-format-attribute -Wformat-security -fno-strict-aliasing -fwrapv -fpic -I/usr/local/pgsql/lib/pgxs/src/makefiles/../../src/pl/plpgsql/src -shared -o plpgsql_check.so plpgsql_check.o -L/usr/local/pgsql/lib -Wl,--as-needed -Wl,-rpath,'/usr/local/pgsql/lib',--enable-new-dtags [pavel@localhost plpgsql_check]$ su root Password: ******* [root@localhost plpgsql_check]# make USE_PGXS=1 install /usr/bin/mkdir -p '/usr/local/pgsql/lib' /usr/bin/mkdir -p '/usr/local/pgsql/share/extension' /usr/bin/mkdir -p '/usr/local/pgsql/share/extension' /usr/bin/install -c -m 755 plpgsql_check.so '/usr/local/pgsql/lib/plpgsql_check.so' /usr/bin/install -c -m 644 plpgsql_check.control '/usr/local/pgsql/share/extension/' /usr/bin/install -c -m 644 plpgsql_check--0.9.sql '/usr/local/pgsql/share/extension/' [root@localhost plpgsql_check]# exit [pavel@localhost plpgsql_check]$ make USE_PGXS=1 installcheck /usr/local/pgsql/lib/pgxs/src/makefiles/../../src/test/regress/pg_regress --inputdir=./ --psqldir='/usr/local/pgsql/bin' --dbname=pl_regression --load-language=plpgsql --dbname=contrib_regression plpgsql_check_passive plpgsql_check_active plpgsql_check_active-9.5 (using postmaster on Unix socket, default port) ============== dropping database "contrib_regression" ============== DROP DATABASE ============== creating database "contrib_regression" ============== CREATE DATABASE ALTER DATABASE ============== installing plpgsql ============== CREATE LANGUAGE ============== running regression test queries ============== test plpgsql_check_passive ... ok test plpgsql_check_active ... ok test plpgsql_check_active-9.5 ... ok ===================== All 3 tests passed. ===================== ## Compilation on Ubuntu Sometimes successful compilation can require libicu-dev package (PostgreSQL 10 and higher - when pg was compiled with ICU support) sudo apt install libicu-dev ## Compilation plpgsql_check on OS X use `-undefined dynamic_lookup` to the last line of the `Makefile ("override CFLAGS += ...")` allowed it to build. ## Compilation plpgsql_check on Windows 7 You can check precompiled dll libraries http://okbob.blogspot.cz/2015/02/plpgsqlcheck-is-available-for-microsoft.html or compile by self: 1. Download and install PostgreSQL 9.3.4 for Win32 from http://www.enterprisedb.com 2. Download and install Microsoft Visual C++ 2010 Express 3. Lern tutorial http://blog.2ndquadrant.com/compiling-postgresql-extensions-visual-studio-windows 4. The plpgsql_check depends on plpgsql and we need to add plpgsql.lib to the library list. Unfortunately PostgreSQL 9.4.3 does not contain this library. 5. Create a plpgsql.lib from plpgsql.dll as described in http://adrianhenke.wordpress.com/2008/12/05/create-lib-file-from-dll 6. Change `plpgsql_check.c` file, add `PGDLLEXPORT` line before evry extension function, as described in http://blog.2ndquadrant.com/compiling-postgresql-extensions-visual-studio-windows (Skip this step if you have a version with "plpgsql_check_builtins.h" header file). 
    ...PGDLLEXPORT
    Datum plpgsql_check_function_tb(PG_FUNCTION_ARGS);
    PGDLLEXPORT
    Datum plpgsql_check_function(PG_FUNCTION_ARGS);
    ...
    PGDLLEXPORT
    Datum
    plpgsql_check_function(PG_FUNCTION_ARGS)
    {
    Oid            funcoid = PG_GETARG_OID(0);
    ...
    PGDLLEXPORT
    Datum
    plpgsql_check_function_tb(PG_FUNCTION_ARGS)
    {
    Oid            funcoid = PG_GETARG_OID(0);
    ...
7. Build plpgsql_check.dll 8. Install plugin 1. copy `plpgsql_check.dll` to `PostgreSQL\9.3\lib` 2. copy `plpgsql_check.control` and `plpgsql_check--0.8.sql` to `PostgreSQL\9.3\share\extension` ## Checked on * gcc on Linux (against all supported PostgreSQL) * clang 3.4 on Linux (against PostgreSQL 9.5) * for success regress tests the PostgreSQL 9.4.5, 9.5 or higher is required Compilation against PostgreSQL 10 requires libICU! # Licence Copyright (c) Pavel Stehule (pavel.stehule@gmail.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # Note If you like it, send a postcard to address Pavel Stehule Skalice 12 256 01 Benesov u Prahy Czech Republic I invite any questions, comments, bug reports, patches on mail address pavel.stehule@gmail.com