From 007e50d8e5a900547471b6c4ec79d9d217682c5d Mon Sep 17 00:00:00 2001 From: Matthew Draper Date: Thu, 27 Oct 2016 15:31:22 -0500 Subject: [PATCH] Permit loads while queries are running A query may wait on a database-level lock, which could lead to a deadlock between threads. --- .../abstract_mysql_adapter.rb | 6 ++- .../mysql/database_statements.rb | 4 +- .../postgresql/database_statements.rb | 8 +++- .../connection_adapters/postgresql_adapter.rb | 10 ++++- .../connection_adapters/sqlite3_adapter.rb | 44 +++++++++++-------- 5 files changed, 47 insertions(+), 25 deletions(-) diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb index 8d0a1c0842..3bee0e2c62 100644 --- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb @@ -215,7 +215,11 @@ module ActiveRecord # Executes the SQL statement in the context of this connection. def execute(sql, name = nil) - log(sql, name) { @connection.query(sql) } + log(sql, name) do + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + @connection.query(sql) + end + end end # Mysql2Adapter doesn't have to free a result after using it, but we use this method diff --git a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb index 56800f7590..274753a8a5 100644 --- a/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb +++ b/activerecord/lib/active_record/connection_adapters/mysql/database_statements.rb @@ -86,7 +86,9 @@ module ActiveRecord end begin - result = stmt.execute(*type_casted_binds) + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + result = stmt.execute(*type_casted_binds) + end rescue Mysql2::Error => e if cache_stmt @statements.delete(sql) diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb index 092543259f..520a50506f 100644 --- a/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb +++ b/activerecord/lib/active_record/connection_adapters/postgresql/database_statements.rb @@ -85,7 +85,9 @@ module ActiveRecord # Queries the database and returns the results in an Array-like object def query(sql, name = nil) #:nodoc: log(sql, name) do - result_as_array @connection.async_exec(sql) + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + result_as_array @connection.async_exec(sql) + end end end @@ -95,7 +97,9 @@ module ActiveRecord # need it specifically, you may want consider the exec_query wrapper. def execute(sql, name = nil) log(sql, name) do - @connection.async_exec(sql) + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + @connection.async_exec(sql) + end end end diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb index acd1eeace7..710b5cd887 100644 --- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb @@ -601,7 +601,11 @@ module ActiveRecord def exec_no_cache(sql, name, binds) type_casted_binds = type_casted_binds(binds) - log(sql, name, binds, type_casted_binds) { @connection.async_exec(sql, type_casted_binds) } + log(sql, name, binds, type_casted_binds) do + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + @connection.async_exec(sql, type_casted_binds) + end + end end def exec_cache(sql, name, binds) @@ -609,7 +613,9 @@ module ActiveRecord type_casted_binds = type_casted_binds(binds) log(sql, name, binds, type_casted_binds, stmt_key) do - @connection.exec_prepared(stmt_key, type_casted_binds) + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + @connection.exec_prepared(stmt_key, type_casted_binds) + end end rescue ActiveRecord::StatementInvalid => e raise unless is_cached_plan_failure?(e) diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb index ebeac425d0..bd73668359 100644 --- a/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb +++ b/activerecord/lib/active_record/connection_adapters/sqlite3_adapter.rb @@ -191,27 +191,29 @@ module ActiveRecord type_casted_binds = type_casted_binds(binds) log(sql, name, binds, type_casted_binds) do - # Don't cache statements if they are not prepared - unless prepare - stmt = @connection.prepare(sql) - begin - cols = stmt.columns - unless without_prepared_statement?(binds) - stmt.bind_params(type_casted_binds) + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + # Don't cache statements if they are not prepared + unless prepare + stmt = @connection.prepare(sql) + begin + cols = stmt.columns + unless without_prepared_statement?(binds) + stmt.bind_params(type_casted_binds) + end + records = stmt.to_a + ensure + stmt.close end + else + cache = @statements[sql] ||= { + stmt: @connection.prepare(sql) + } + stmt = cache[:stmt] + cols = cache[:cols] ||= stmt.columns + stmt.reset! + stmt.bind_params(type_casted_binds) records = stmt.to_a - ensure - stmt.close end - else - cache = @statements[sql] ||= { - stmt: @connection.prepare(sql) - } - stmt = cache[:stmt] - cols = cache[:cols] ||= stmt.columns - stmt.reset! - stmt.bind_params(type_casted_binds) - records = stmt.to_a end ActiveRecord::Result.new(cols, records) @@ -229,7 +231,11 @@ module ActiveRecord end def execute(sql, name = nil) #:nodoc: - log(sql, name) { @connection.execute(sql) } + log(sql, name) do + ActiveSupport::Dependencies.interlock.permit_concurrent_loads do + @connection.execute(sql) + end + end end def begin_db_transaction #:nodoc: