create table if not exists candles (
    id bigserial not null,
    instrument_id bigint not null references instruments(id),
    timeframe text not null,
    ts_open timestamptz not null,
    ts_close timestamptz not null,
    open numeric(20,10) not null,
    high numeric(20,10) not null,
    low numeric(20,10) not null,
    close numeric(20,10) not null,
    volume numeric(28,10),
    source text not null default 'api',
    created_at timestamptz not null default now(),
    primary key (id, ts_open),
    unique (instrument_id, timeframe, ts_open)
) partition by range (ts_open);