Fix race condition with multiple runners

This commit is contained in:
Diggory Blake 2022-02-08 13:10:05 +00:00
parent 7a13e04b21
commit 989b11ffe0
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GPG key ID: E6BDFA83146ABD40
4 changed files with 125 additions and 3 deletions

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@ -1,6 +1,6 @@
[package]
name = "sqlxmq"
version = "0.3.4"
version = "0.3.5"
authors = ["Diggory Blake <diggsey@googlemail.com>"]
edition = "2018"
license = "MIT OR Apache-2.0"
@ -23,7 +23,7 @@ uuid = { version = "0.8.2", features = ["v4"] }
log = "0.4.14"
serde_json = "1.0.64"
serde = "1.0.124"
sqlxmq_macros = { version = "0.3.4", path = "sqlxmq_macros" }
sqlxmq_macros = { version = "0.3.5", path = "sqlxmq_macros" }
anymap2 = "0.13.0"
[features]

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@ -0,0 +1,60 @@
-- Main entry-point for job runner: pulls a batch of messages from the queue.
CREATE OR REPLACE FUNCTION mq_poll(channel_names TEXT[], batch_size INT DEFAULT 1)
RETURNS TABLE(
id UUID,
is_committed BOOLEAN,
name TEXT,
payload_json TEXT,
payload_bytes BYTEA,
retry_backoff INTERVAL,
wait_time INTERVAL
) AS $$
BEGIN
RETURN QUERY UPDATE mq_msgs
SET
attempt_at = CASE WHEN mq_msgs.attempts = 1 THEN NULL ELSE NOW() + mq_msgs.retry_backoff END,
attempts = mq_msgs.attempts - 1,
retry_backoff = mq_msgs.retry_backoff * 2
FROM (
SELECT
msgs.id
FROM mq_active_channels(channel_names, batch_size) AS active_channels
INNER JOIN LATERAL (
SELECT * FROM mq_msgs
WHERE mq_msgs.id != uuid_nil()
AND mq_msgs.attempt_at <= NOW()
AND mq_msgs.channel_name = active_channels.name
AND mq_msgs.channel_args = active_channels.args
AND NOT mq_uuid_exists(mq_msgs.after_message_id)
ORDER BY mq_msgs.attempt_at ASC
LIMIT batch_size
) AS msgs ON TRUE
LIMIT batch_size
) AS messages_to_update
LEFT JOIN mq_payloads ON mq_payloads.id = messages_to_update.id
WHERE mq_msgs.id = messages_to_update.id
RETURNING
mq_msgs.id,
mq_msgs.commit_interval IS NULL,
mq_payloads.name,
mq_payloads.payload_json::TEXT,
mq_payloads.payload_bytes,
mq_msgs.retry_backoff / 2,
interval '0' AS wait_time;
IF NOT FOUND THEN
RETURN QUERY SELECT
NULL::UUID,
NULL::BOOLEAN,
NULL::TEXT,
NULL::TEXT,
NULL::BYTEA,
NULL::INTERVAL,
MIN(mq_msgs.attempt_at) - NOW()
FROM mq_msgs
WHERE mq_msgs.id != uuid_nil()
AND NOT mq_uuid_exists(mq_msgs.after_message_id)
AND (channel_names IS NULL OR mq_msgs.channel_name = ANY(channel_names));
END IF;
END;
$$ LANGUAGE plpgsql;

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@ -0,0 +1,62 @@
-- Main entry-point for job runner: pulls a batch of messages from the queue.
CREATE OR REPLACE FUNCTION mq_poll(channel_names TEXT[], batch_size INT DEFAULT 1)
RETURNS TABLE(
id UUID,
is_committed BOOLEAN,
name TEXT,
payload_json TEXT,
payload_bytes BYTEA,
retry_backoff INTERVAL,
wait_time INTERVAL
) AS $$
BEGIN
RETURN QUERY UPDATE mq_msgs
SET
attempt_at = CASE WHEN mq_msgs.attempts = 1 THEN NULL ELSE NOW() + mq_msgs.retry_backoff END,
attempts = mq_msgs.attempts - 1,
retry_backoff = mq_msgs.retry_backoff * 2
FROM (
SELECT
msgs.id
FROM mq_active_channels(channel_names, batch_size) AS active_channels
INNER JOIN LATERAL (
SELECT mq_msgs.id FROM mq_msgs
WHERE mq_msgs.id != uuid_nil()
AND mq_msgs.attempt_at <= NOW()
AND mq_msgs.channel_name = active_channels.name
AND mq_msgs.channel_args = active_channels.args
AND NOT mq_uuid_exists(mq_msgs.after_message_id)
ORDER BY mq_msgs.attempt_at ASC
LIMIT batch_size
) AS msgs ON TRUE
LIMIT batch_size
) AS messages_to_update
LEFT JOIN mq_payloads ON mq_payloads.id = messages_to_update.id
WHERE mq_msgs.id = messages_to_update.id
AND mq_msgs.attempt_at <= NOW()
RETURNING
mq_msgs.id,
mq_msgs.commit_interval IS NULL,
mq_payloads.name,
mq_payloads.payload_json::TEXT,
mq_payloads.payload_bytes,
mq_msgs.retry_backoff / 2,
interval '0' AS wait_time;
IF NOT FOUND THEN
RETURN QUERY SELECT
NULL::UUID,
NULL::BOOLEAN,
NULL::TEXT,
NULL::TEXT,
NULL::BYTEA,
NULL::INTERVAL,
MIN(mq_msgs.attempt_at) - NOW()
FROM mq_msgs
WHERE mq_msgs.id != uuid_nil()
AND NOT mq_uuid_exists(mq_msgs.after_message_id)
AND (channel_names IS NULL OR mq_msgs.channel_name = ANY(channel_names));
END IF;
END;
$$ LANGUAGE plpgsql;

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@ -1,6 +1,6 @@
[package]
name = "sqlxmq_macros"
version = "0.3.4"
version = "0.3.5"
authors = ["Diggory Blake <diggsey@googlemail.com>"]
edition = "2018"
license = "MIT OR Apache-2.0"