Invalidate statement cache on schema changes affecting statement result. #103
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asyncpg/connection.py
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| if not state.closed: | ||
| return state | ||
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| return await self._prepare_statement(query, timeout, cache) |
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Don't split the _get_statement method please.
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asyncpg/exceptions/_base.py
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| class InvalidCachedStatementError(AsyncpgError): | ||
| """Cached statement is not longer valid.""" |
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asyncpg/prepared_stmt.py
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| if e.server_source_function == 'RevalidateCachedQuery': | ||
| # Handle query plan rejection due to schema or config changes. | ||
| # See comment in Connection._do_execute. | ||
| raise exceptions.InvalidCachedStatementError( |
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Can we move this logic to PostgresMessage.new()?
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| def is_in_transaction(self): | ||
| return self.xact_status == PQTRANS_INTRANS | ||
| return self.xact_status in (PQTRANS_INTRANS, PQTRANS_INERROR) |
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Add a comment here why PQTRANS_INERROR?
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asyncpg/connection.py
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| # connection belongs to (if any). | ||
| # | ||
| # Note that we specifically do not rely on the error | ||
| # message, as it is localizable. |
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| if self._protocol.is_in_transaction(): | ||
| raise | ||
| else: | ||
| stmt = await self._get_statement(query, timeout) |
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Add a comment explaining that we only do 1 retry.
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tests/test_cache_invalidation.py
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| finally: | ||
| await self.con.execute('DROP TABLE tab1') | ||
| await pool.release(con2) | ||
| await pool.release(con1) |
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You don't need to release connections if you're closing the pool
PostgreSQL will raise an exception when it detects that the result type of the query has changed from when the statement was prepared. This may happen, for example, after an ALTER TABLE or SET search_path. When this happens, and there is no transaction running, we can simply re-prepare the statement and try again. If the transaction _is_ running, this error will put it into an error state, and we have no choice but to raise an exception. The original error is somewhat cryptic, so we raise a custom InvalidCachedStatementError with the original server exception as context. In either case we clear the statement cache for this connection and all other connections of the pool this connection belongs to (if any). See #72 and #76 for discussion. Fixes: #72.
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PostgreSQL will raise an exception when it detects that the result type of the
query has changed from when the statement was prepared. This may happen, for
example, after an ALTER TABLE or SET search_path.
When this happens, and there is no transaction running, we can simply
re-prepare the statement and try again.
If the transaction is running, this error will put it into an error state,
and we have no choice but to raise an exception. The original error is
somewhat cryptic, so we raise a custom InvalidCachedStatementError with the
original server exception as context.
In either case we clear the statement cache for this connection and all other
connections of the pool this connection belongs to (if any).
See #72 and #76 for discussion.
Fixes: #72.