kshvakov

Software Transactional Memory in C++: pure functional approach (Tutorial)

In this article I’ll tell you about my pure functional library for Software Transactional Memory (STM) that I’ve built in C++. I adopted some advanced functional programming concepts that make it composable and convenient to use. Its implementation is rather small and robust, which differentiates the library from competitors. Let’s discuss what STM is and how to use it.

Links

• The cpp_stm_free library
• Dining Philosophers sample
• More STM samples
• C++ Russia 2018 talk slides (Eng)

kshvakov

create or replace function scheduler.run_tasks() returns void as $$
    declare
        _function_name     varchar;
        _sqlstate          text;
        _message           text;
        _exception_detail  text;
        _exception_hint    text;
        _exception_context text;
        _run_tasks_counter bigint;
        _start_time        timestamp with time zone;

kshvakov

Требования

Для работы необходим PostgreSQL-server 9.5 и, более-менее "свежий", Docker

Настройка сервера баз данных

Т.к. app-server и worker работают в docker-контейнерах, то следует прописать его (докера) сеть в pg_hba.conf

host    all             all  172.17.0.0/24 password

kshvakov

$ time ./try_advisory_lock 
Waiting
[5] Done, processed 1274 rows.
[7] Done, processed 1236 rows.
[2] Done, processed 1252 rows.
[4] Done, processed 1237 rows.
[8] Done, processed 1257 rows.
[6] Done, processed 1257 rows.
[3] Done, processed 1244 rows.
[1] Done, processed 1243 rows.

kshvakov

do $$
declare 
    _rawjson json;
    _item    record;
    _id      int;
    _param   text;
begin
    for _rawjson in select * from json_array_elements('[{"id" : 42, "params" : ["bad", "sad"] }]'::json) loop 
            _item = (select j from json_to_record(_rawjson) AS j (
                    id     int, 

kshvakov

--- src/bin/pg_basebackup/pg_basebackup_origin.c	2016-03-24 12:42:30.312362751 +0300
+++ src/bin/pg_basebackup/pg_basebackup.c	2016-03-24 09:45:40.804376436 +0300
@@ -239,6 +239,7 @@
 	  "                         (in kB/s, or use suffix \"k\" or \"M\")\n"));
 	printf(_("  -R, --write-recovery-conf\n"
 			 "                         write recovery.conf after backup\n"));
+	printf(_("  -S, --slot=SLOTNAME    replication slot to use\n"));
 	printf(_("  -T, --tablespace-mapping=OLDDIR=NEWDIR\n"
 	  "                         relocate tablespace in OLDDIR to NEWDIR\n"));
 	printf(_("  -x, --xlog             include required WAL files in backup (fetch mode)\n"));