diff options
Diffstat (limited to 'lib/sqlalchemy/databases/firebird.py')
| -rw-r--r-- | lib/sqlalchemy/databases/firebird.py | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/lib/sqlalchemy/databases/firebird.py b/lib/sqlalchemy/databases/firebird.py index 8b7a41aac..a86dfb23f 100644 --- a/lib/sqlalchemy/databases/firebird.py +++ b/lib/sqlalchemy/databases/firebird.py @@ -59,6 +59,25 @@ on the ``FBDialect`` class to do whatever is needed:: # instead of ``char_length`` FBCompiler.LENGTH_FUNCTION_NAME = 'strlen' +Pooling connections +------------------- + +The default strategy used by SQLAlchemy to pool the database connections +in particular cases may raise an ``OperationalError`` with a message +`"object XYZ is in use"`. This happens on Firebird when there are two +connections to the database, one is using, or has used, a particular table +and the other tries to drop or alter the same table. To garantee DDL +operations success Firebird recommend doing them as the single connected user. + +In case your SA application effectively needs to do DDL operations while other +connections are active, the following setting may alleviate the problem:: + + from sqlalchemy import pool + from sqlalchemy.databases.firebird import dialect + + # Force SA to use a single connection per thread + dialect.poolclass = pool.SingletonThreadPool + .. [#] Well, that is not the whole story, as the client may still ask a different (lower) dialect... @@ -71,7 +90,7 @@ on the ``FBDialect`` class to do whatever is needed:: import datetime import warnings -from sqlalchemy import exceptions, pool, schema, types as sqltypes, sql, util +from sqlalchemy import exceptions, schema, types as sqltypes, sql, util from sqlalchemy.engine import base, default @@ -655,7 +674,6 @@ class FBIdentifierPreparer(sql.compiler.IdentifierPreparer): dialect = FBDialect -dialect.poolclass = pool.SingletonThreadPool dialect.statement_compiler = FBCompiler dialect.schemagenerator = FBSchemaGenerator dialect.schemadropper = FBSchemaDropper |