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Fixup reserve_with_scope_using_optimized_postgres
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A touch of re-arranging after rubocop complaints
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albus522 committed Aug 14, 2024
1 parent a50c45b commit aa37138
Showing 1 changed file with 11 additions and 7 deletions.
18 changes: 11 additions & 7 deletions lib/delayed/backend/active_record.rb
Original file line number Diff line number Diff line change
Expand Up @@ -133,19 +133,23 @@ def self.reserve_with_scope_using_optimized_postgres(ready_scope, worker, now)
# Note: active_record would attempt to generate UPDATE...LIMIT like
# SQL for Postgres if we use a .limit() filter, but it would not
# use 'FOR UPDATE' and we would have many locking conflicts
subquery = ready_scope.limit(1).lock(true).select("id").to_sql

# On PostgreSQL >= 9.5 we leverage SKIP LOCK to avoid multiple workers blocking each other
# when attempting to get the next available job
# https://www.postgresql.org/docs/9.5/sql-select.html#SQL-FOR-UPDATE-SHARE
skip_locked = ""
if connection.respond_to?(:postgresql_version) && connection.postgresql_version >= 90500
skip_locked = " SKIP LOCKED"
if connection.respond_to?(:postgresql_version) && connection.postgresql_version >= 9_05_00 # rubocop:disable Style/NumericLiterals
subquery << " SKIP LOCKED"
end

quoted_name = connection.quote_table_name(table_name)
subquery = ready_scope.limit(1).lock(true).select("id").to_sql
sql = "UPDATE #{quoted_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery}#{skip_locked}) RETURNING *"
reserved = find_by_sql([sql, now, worker.name])
reserved[0]
find_by_sql(
[
"UPDATE #{quoted_name} SET locked_at = ?, locked_by = ? WHERE id IN (#{subquery}) RETURNING *",
now,
worker.name
]
).first
end

def self.reserve_with_scope_using_optimized_mysql(ready_scope, worker, now)
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