Add adapter level read-only transaction support#741
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- Add adapter-level read_only_transaction callbacks for SQL adapters - Update mix ecto.query to use the transaction read_only opt instead of adapter-specific transaction SQL.
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v0idpwn
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Jul 13, 2026
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| @impl true | ||
| def read_only_transaction(conn, opts, fun) do | ||
| {:ok, _} = query(conn, "SET TRANSACTION READ ONLY", [], log: nil) |
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Don't we log the BEGIN/END in the transaction? If yes, we should log this too.
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| @impl true | ||
| def read_only_transaction(_conn, _opts, _fun) do | ||
| raise ArgumentError, "read-only transactions are not supported by Ecto.Adapters.Tds" |
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Can maybe not implement the callback and get the very same error
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| @impl true | ||
| def read_only_transaction(conn, opts, fun) do | ||
| {:ok, _} = query(conn, "SET TRANSACTION READ ONLY", [], log: nil) |
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I guess this is more involved, but some databases allow you to set the transaction to read-only in the begin statement. This would be one less query round trip, if it's achievable.
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I think this is a good starting point and we should move it to the adapters next.
- Log SET TRANSACTION READ ONLY through the transaction logger - Remove the TDS read_only_transaction callback so Ecto.Adapters.SQL raises the unsupported adapter error
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Adds
repo.transaction(read_only: true)support for SQL adapters by moving the read-only transaction handling into adapter-level connection callbacks.This lets
mix ecto.queryuse the shared transaction option instead of adapter-specific transaction SQL itself.Closes #736.