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Merge branch '2.3' into develop

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Markus Mäkelä
2019-04-01 11:31:49 +03:00
parent 4276514e27 738ae9178b
commit e659c6cc73
15 changed files with 200 additions and 73 deletions
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21
Documentation/Routers/ReadWriteSplit.md
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@ -438,23 +438,10 @@ failure of a master node without any visible effects to the client.
If no replacement node becomes available before the timeout controlled by
`delayed_retry_timeout` is exceeded, the client connection is closed.
Not all transactions can be safely replayed. Only when the following criteria
are met, the transaction can be safely replayed.
* Transaction contains only data modification (`INSERT`, `UPDATE`, `DELETE`
etc.) or `SELECT ... FOR UPDATE` statements.
* The replacement server where the transaction is applied returns results
identical to the original partial transaction.
If the results from the replacement server are not identical when the transaction is
replayed, the client connection is closed. This means that any transaction with a server
specific result (e.g. `NOW()`, `@@server_id`) cannot be replayed successfully.
Performing MVCC reads (`SELECT` queries without `FOR UPDATE` or `LOCK IN SHARE MODE`)
with transaction replay is discouraged. If such statements are executed
but the results of each reply are identical, the transaction is replayed but the results
are not guaranteed to be consistent on the database level.
If the results from the replacement server are not identical when the
transaction is replayed, the client connection is closed. This means that any
transaction with a server specific result (e.g. `NOW()`, `@@server_id`) cannot
be replayed successfully but it will still be attempted.
### `transaction_replay_max_size`