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-- ----------------------------------------------------------------------
-- Section: Internal Tables
--
-- Overview:
-- pgq.queue - Queue configuration
-- pgq.consumer - Consumer names
-- pgq.subscription - Consumer registrations
-- pgq.tick - Per-queue snapshots (ticks)
-- pgq.event_* - Data tables
-- pgq.retry_queue - Events to be retried later
--
--
-- Standard triggers store events in the pgq.event_* data tables
-- There is one top event table pgq.event_<queue_id> for each queue
-- inherited from pgq.event_template wuith three tables for actual data
-- pgq.event_<queue_id>_0 to pgq.event_<queue_id>_2.
--
-- The active table is rotated at interval, so that if all the consubers
-- have passed some poin the oldes one can be emptied using TRUNCATE command
-- for efficiency
--
--
-- ----------------------------------------------------------------------
set client_min_messages = 'warning';
set default_with_oids = 'off';
-- drop schema if exists pgq cascade;
create schema pgq;
-- ----------------------------------------------------------------------
-- Table: pgq.consumer
--
-- Name to id lookup for consumers
--
-- Columns:
-- co_id - consumer's id for internal usage
-- co_name - consumer's id for external usage
-- ----------------------------------------------------------------------
create table pgq.consumer (
co_id serial,
co_name text not null,
constraint consumer_pkey primary key (co_id),
constraint consumer_name_uq UNIQUE (co_name)
);
-- ----------------------------------------------------------------------
-- Table: pgq.queue
--
-- Information about available queues
--
-- Columns:
-- queue_id - queue id for internal usage
-- queue_name - queue name visible outside
-- queue_ntables - how many data tables the queue has
-- queue_cur_table - which data table is currently active
-- queue_rotation_period - period for data table rotation
-- queue_switch_step1 - tx when rotation happened
-- queue_switch_step2 - tx after rotation was committed
-- queue_switch_time - time when switch happened
-- queue_external_ticker - ticks come from some external sources
-- queue_ticker_paused - ticker is paused
-- queue_disable_insert - disallow pgq.insert_event()
-- queue_ticker_max_count - batch should not contain more events
-- queue_ticker_max_lag - events should not age more
-- queue_ticker_idle_period - how often to tick when no events happen
-- queue_per_tx_limit - Max number of events single TX can insert
-- queue_data_pfx - prefix for data table names
-- queue_event_seq - sequence for event id's
-- queue_tick_seq - sequence for tick id's
-- ----------------------------------------------------------------------
create table pgq.queue (
queue_id serial,
queue_name text not null,
queue_ntables integer not null default 3,
queue_cur_table integer not null default 0,
queue_rotation_period interval not null default '2 hours',
queue_switch_step1 bigint not null default txid_current(),
queue_switch_step2 bigint default txid_current(),
queue_switch_time timestamptz not null default now(),
queue_external_ticker boolean not null default false,
queue_disable_insert boolean not null default false,
queue_ticker_paused boolean not null default false,
queue_ticker_max_count integer not null default 500,
queue_ticker_max_lag interval not null default '3 seconds',
queue_ticker_idle_period interval not null default '1 minute',
queue_per_tx_limit integer,
queue_data_pfx text not null,
queue_event_seq text not null,
queue_tick_seq text not null,
constraint queue_pkey primary key (queue_id),
constraint queue_name_uq unique (queue_name)
);
-- ----------------------------------------------------------------------
-- Table: pgq.tick
--
-- Snapshots for event batching
--
-- Columns:
-- tick_queue - queue id whose tick it is
-- tick_id - ticks id (per-queue)
-- tick_time - time when tick happened
-- tick_snapshot - transaction state
-- tick_event_seq - last value for event seq
-- ----------------------------------------------------------------------
create table pgq.tick (
tick_queue int4 not null,
tick_id bigint not null,
tick_time timestamptz not null default now(),
tick_snapshot txid_snapshot not null default txid_current_snapshot(),
tick_event_seq bigint not null, -- may be NULL on upgraded dbs
constraint tick_pkey primary key (tick_queue, tick_id),
constraint tick_queue_fkey foreign key (tick_queue)
references pgq.queue (queue_id)
);
-- ----------------------------------------------------------------------
-- Sequence: pgq.batch_id_seq
--
-- Sequence for batch id's.
-- ----------------------------------------------------------------------
create sequence pgq.batch_id_seq;
-- ----------------------------------------------------------------------
-- Table: pgq.subscription
--
-- Consumer registration on a queue.
--
-- Columns:
--
-- sub_id - subscription id for internal usage
-- sub_queue - queue id
-- sub_consumer - consumer's id
-- sub_last_tick - last tick the consumer processed
-- sub_batch - shortcut for queue_id/consumer_id/tick_id
-- sub_next_tick - batch end pos
-- ----------------------------------------------------------------------
create table pgq.subscription (
sub_id serial not null,
sub_queue int4 not null,
sub_consumer int4 not null,
sub_last_tick bigint,
sub_active timestamptz not null default now(),
sub_batch bigint,
sub_next_tick bigint,
constraint subscription_pkey primary key (sub_queue, sub_consumer),
constraint subscription_batch_idx unique (sub_batch),
constraint sub_queue_fkey foreign key (sub_queue)
references pgq.queue (queue_id),
constraint sub_consumer_fkey foreign key (sub_consumer)
references pgq.consumer (co_id)
);
-- ----------------------------------------------------------------------
-- Table: pgq.event_template
--
-- Parent table for all event tables
--
-- Columns:
-- ev_id - event's id, supposed to be unique per queue
-- ev_time - when the event was inserted
-- ev_txid - transaction id which inserted the event
-- ev_owner - subscription id that wanted to retry this
-- ev_retry - how many times the event has been retried, NULL for new events
-- ev_type - consumer/producer can specify what the data fields contain
-- ev_data - data field
-- ev_extra1 - extra data field
-- ev_extra2 - extra data field
-- ev_extra3 - extra data field
-- ev_extra4 - extra data field
-- ----------------------------------------------------------------------
create table pgq.event_template (
ev_id bigint not null,
ev_time timestamptz not null,
ev_txid bigint not null default txid_current(),
ev_owner int4,
ev_retry int4,
ev_type text,
ev_data text,
ev_extra1 text,
ev_extra2 text,
ev_extra3 text,
ev_extra4 text
);
-- ----------------------------------------------------------------------
-- Table: pgq.retry_queue
--
-- Events to be retried. When retry time reaches, they will
-- be put back into main queue.
--
-- Columns:
-- ev_retry_after - time when it should be re-inserted to main queue
-- ev_queue - queue id, used to speed up event copy into queue
-- * - same as pgq.event_template
-- ----------------------------------------------------------------------
create table pgq.retry_queue (
ev_retry_after timestamptz not null,
ev_queue int4 not null,
like pgq.event_template,
constraint rq_pkey primary key (ev_owner, ev_id),
constraint rq_queue_id_fkey foreign key (ev_queue)
references pgq.queue (queue_id)
);
alter table pgq.retry_queue alter column ev_owner set not null;
alter table pgq.retry_queue alter column ev_txid drop not null;
create index rq_retry_idx on pgq.retry_queue (ev_retry_after);
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