Commit 795a6c59 authored by Brett Walker's avatar Brett Walker Committed by Stan Hu

Renaming of "xlog" to "wal" for PostgreSQL 10

parent 858af8e3
......@@ -20,7 +20,8 @@ class PgReplicationSlot
# http://bdr-project.org/docs/stable/monitoring-peers.html
def self.slots_retained_bytes
ActiveRecord::Base.connection.execute(<<-SQL.squish)
SELECT slot_name, database, active, pg_xlog_location_diff(pg_current_xlog_insert_location(), restart_lsn)
SELECT slot_name, database,
active, #{Gitlab::Database.pg_wal_lsn_diff}(#{Gitlab::Database.pg_current_wal_insert_lsn}(), restart_lsn)
AS retained_bytes
FROM pg_replication_slots;
SQL
......@@ -30,7 +31,7 @@ class PgReplicationSlot
# returns the max number WAL space (in bytes) being used across the replication slots
def self.max_retained_wal
ActiveRecord::Base.connection.execute(<<-SQL.squish)
SELECT COALESCE(MAX(pg_xlog_location_diff(pg_current_xlog_insert_location(), restart_lsn)), 0)
SELECT COALESCE(MAX(#{Gitlab::Database.pg_wal_lsn_diff}(#{Gitlab::Database.pg_current_wal_insert_lsn}(), restart_lsn)), 0)
FROM pg_replication_slots;
SQL
.first.fetch('coalesce').to_i
......
......@@ -63,7 +63,7 @@ module Gitlab
def data_is_recent_enough?
# It's possible for a replica to not replay WAL data for a while,
# despite being up to date. This can happen when a primary does not
# receive any writes a for a while.
# receive any writes for a while.
#
# To prevent this from happening we check if the lag size (in bytes)
# of the replica is small enough for the replica to be useful. We
......@@ -92,7 +92,10 @@ module Gitlab
# This method will return nil if no lag size could be calculated.
def replication_lag_size
location = connection.quote(primary_write_location)
row = query_and_release("SELECT pg_xlog_location_diff(#{location}, pg_last_xlog_replay_location())::float AS diff")
row = query_and_release(<<-SQL.squish)
SELECT #{Gitlab::Database.pg_wal_lsn_diff}(#{location}, #{Gitlab::Database.pg_last_wal_replay_lsn}())::float
AS diff
SQL
row['diff'].to_i if row.any?
end
......@@ -110,11 +113,14 @@ module Gitlab
def caught_up?(location)
string = connection.quote(location)
# In case the host is a primary pg_last_xlog_replay_location() returns
# In case the host is a primary pg_last_wal_replay_lsn/pg_last_xlog_replay_location() returns
# NULL. The recovery check ensures we treat the host as up-to-date in
# such a case.
query = "SELECT NOT pg_is_in_recovery() OR " \
"pg_xlog_location_diff(pg_last_xlog_replay_location(), #{string}) >= 0 AS result"
query = <<-SQL.squish
SELECT NOT pg_is_in_recovery()
OR #{Gitlab::Database.pg_wal_lsn_diff}(#{Gitlab::Database.pg_last_wal_replay_lsn}(), #{string}) >= 0
AS result
SQL
row = query_and_release(query)
......
......@@ -89,7 +89,7 @@ module Gitlab
def primary_write_location
read_write do |connection|
row = connection
.select_all('SELECT pg_current_xlog_insert_location()::text AS location')
.select_all("SELECT #{Gitlab::Database.pg_current_wal_insert_lsn}()::text AS location")
.first
if row
......
......@@ -76,14 +76,15 @@ module Gitlab
def self.db_replication_lag_seconds
# Obtain the replication lag in seconds
lag =
ActiveRecord::Base.connection.execute('
SELECT CASE
WHEN pg_last_xlog_receive_location() = pg_last_xlog_replay_location()
THEN 0
ELSE
EXTRACT (EPOCH FROM now() - pg_last_xact_replay_timestamp())::INTEGER
END
AS replication_lag')
ActiveRecord::Base.connection.execute(<<-SQL.squish)
SELECT CASE
WHEN #{Gitlab::Database.pg_last_wal_receive_lsn}() = #{Gitlab::Database.pg_last_wal_receive_lsn}()
THEN 0
ELSE
EXTRACT (EPOCH FROM now() - pg_last_xact_replay_timestamp())::INTEGER
END
AS replication_lag
SQL
.first
.fetch('replication_lag')
......
......@@ -7,9 +7,11 @@ describe PgReplicationSlot, :postgresql do
expect(described_class.max_replication_slots).to be >= 0
end
skip = PgReplicationSlot.max_replication_slots <= PgReplicationSlot.count
context 'with enough slots available', skip: (skip ? 'max_replication_slots too small' : nil) do
skip_examples = PgReplicationSlot.max_replication_slots <= PgReplicationSlot.count
context 'with enough slots available' do
before(:all) do
skip('max_replication_slots too small') if skip_examples
@current_slot_count =
ActiveRecord::Base.connection.execute("SELECT COUNT(*) FROM pg_replication_slots;")
.first.fetch('count').to_i
......@@ -21,7 +23,9 @@ describe PgReplicationSlot, :postgresql do
end
after(:all) do
ActiveRecord::Base.connection.execute("SELECT pg_drop_replication_slot('test_slot');")
unless skip_examples
ActiveRecord::Base.connection.execute("SELECT pg_drop_replication_slot('test_slot');")
end
end
it '#slots_count' do
......
......@@ -46,6 +46,10 @@ module Gitlab
database_version.match(/\A(?:PostgreSQL |)([^\s]+).*\z/)[1]
end
def self.postgresql_9_or_less?
postgresql? && version.to_f < 10
end
def self.join_lateral_supported?
postgresql? && version.to_f >= 9.3
end
......@@ -58,6 +62,24 @@ module Gitlab
postgresql? && version.to_f >= 9.6
end
# map some of the function names that changed between PostgreSQL 9 and 10
# https://wiki.postgresql.org/wiki/New_in_postgres_10
def self.pg_wal_lsn_diff
Gitlab::Database.postgresql_9_or_less? ? 'pg_xlog_location_diff' : 'pg_wal_lsn_diff'
end
def self.pg_current_wal_insert_lsn
Gitlab::Database.postgresql_9_or_less? ? 'pg_current_xlog_insert_location' : 'pg_current_wal_insert_lsn'
end
def self.pg_last_wal_receive_lsn
Gitlab::Database.postgresql_9_or_less? ? 'pg_last_xlog_receive_location' : 'pg_last_wal_receive_lsn'
end
def self.pg_last_wal_replay_lsn
Gitlab::Database.postgresql_9_or_less? ? 'pg_last_xlog_replay_location' : 'pg_last_wal_replay_lsn'
end
def self.nulls_last_order(field, direction = 'ASC')
order = "#{field} #{direction}"
......
......@@ -51,6 +51,28 @@ describe Gitlab::Database do
end
end
describe '.postgresql_9_or_less?' do
it 'returns false when using MySQL' do
allow(described_class).to receive(:postgresql?).and_return(false)
expect(described_class.postgresql_9_or_less?).to eq(false)
end
it 'returns true when using PostgreSQL 9.6' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('9.6')
expect(described_class.postgresql_9_or_less?).to eq(true)
end
it 'returns false when using PostgreSQL 10 or newer' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('10')
expect(described_class.postgresql_9_or_less?).to eq(false)
end
end
describe '.join_lateral_supported?' do
it 'returns false when using MySQL' do
allow(described_class).to receive(:postgresql?).and_return(false)
......@@ -95,6 +117,70 @@ describe Gitlab::Database do
end
end
describe '.pg_wal_lsn_diff' do
it 'returns old name when using PostgreSQL 9.6' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('9.6')
expect(described_class.pg_wal_lsn_diff).to eq('pg_xlog_location_diff')
end
it 'returns new name when using PostgreSQL 10 or newer' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('10')
expect(described_class.pg_wal_lsn_diff).to eq('pg_wal_lsn_diff')
end
end
describe '.pg_current_wal_insert_lsn' do
it 'returns old name when using PostgreSQL 9.6' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('9.6')
expect(described_class.pg_current_wal_insert_lsn).to eq('pg_current_xlog_insert_location')
end
it 'returns new name when using PostgreSQL 10 or newer' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('10')
expect(described_class.pg_current_wal_insert_lsn).to eq('pg_current_wal_insert_lsn')
end
end
describe '.pg_last_wal_receive_lsn' do
it 'returns old name when using PostgreSQL 9.6' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('9.6')
expect(described_class.pg_last_wal_receive_lsn).to eq('pg_last_xlog_receive_location')
end
it 'returns new name when using PostgreSQL 10 or newer' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('10')
expect(described_class.pg_last_wal_receive_lsn).to eq('pg_last_wal_receive_lsn')
end
end
describe '.pg_last_wal_replay_lsn' do
it 'returns old name when using PostgreSQL 9.6' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('9.6')
expect(described_class.pg_last_wal_replay_lsn).to eq('pg_last_xlog_replay_location')
end
it 'returns new name when using PostgreSQL 10 or newer' do
allow(described_class).to receive(:postgresql?).and_return(true)
allow(described_class).to receive(:version).and_return('10')
expect(described_class.pg_last_wal_replay_lsn).to eq('pg_last_wal_replay_lsn')
end
end
describe '.nulls_last_order' do
context 'when using PostgreSQL' do
before do
......
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