When you develop some changes it may happen you need to add new indexes to all existing partitions of some parent table. It happened to me several times already. Therefore I put here this small pl/pgsql script which can help with it. Script creates indexes using dblink so it can be canceled any time. And if you restart it it checks if index already exists.

do $$ 
	_tab record;
	colnames text;
	querymask text;
	query text;
	_col record;
	indexexists int;
	ret text;

	for _tab in (
	relnamespace::regnamespace::text as schemaname,
	relnamespace::regnamespace::text||'.'||relname as fullname, 
	relname as shortname 
	from pg_class where oid in (
	select inhrelid from pg_inherits 
	where inhparent::regclass::text like '%...your_parent_table...')
	order by 2 desc) loop

		querymask := 'create index '||_tab.shortname||'_${INDEXNAME} on '||_tab.fullname||' ${COLUMNS}';
		raise notice 'querymask: %', querymask;
		for _col in (
		select * from (
		values('index1','(col1, col2)'),
		('index2','(col2, col3)'),
		('index3','(col4)') ) as t(indexname, colnames)
		) loop
			select count(*) into indexexists from pg_indexes i 
			where i.schemaname=_tab.schemaname and 
			i.tablename=_tab.shortname and

			if indexexists = 0 then
				query := replace(querymask, '${INDEXNAME}', _col.indexname);
				query := replace(query, '${COLUMNS}', _col.colnames);
				raise notice 'query: %', query;
				select dblink_exec('dbname='||current_database(),query) into ret;
				raise notice 'result: %', ret;
			end if;
		end loop;
	end loop;

$$ language plpgsql;