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Diffstat (limited to 'docs/tcp_replication.md')
| -rw-r--r-- | docs/tcp_replication.md | 50 |
1 files changed, 18 insertions, 32 deletions
diff --git a/docs/tcp_replication.md b/docs/tcp_replication.md index e3a4634b14..3be8e50c4c 100644 --- a/docs/tcp_replication.md +++ b/docs/tcp_replication.md @@ -14,16 +14,16 @@ example flow would be (where '>' indicates master to worker and '<' worker to master flows): > SERVER example.com - < REPLICATE events 53 + < REPLICATE + > POSITION events 53 > RDATA events 54 ["$foo1:bar.com", ...] > RDATA events 55 ["$foo4:bar.com", ...] -The example shows the server accepting a new connection and sending its -identity with the `SERVER` command, followed by the client asking to -subscribe to the `events` stream from the token `53`. The server then -periodically sends `RDATA` commands which have the format -`RDATA <stream_name> <token> <row>`, where the format of `<row>` is -defined by the individual streams. +The example shows the server accepting a new connection and sending its identity +with the `SERVER` command, followed by the client server to respond with the +position of all streams. The server then periodically sends `RDATA` commands +which have the format `RDATA <stream_name> <token> <row>`, where the format of +`<row>` is defined by the individual streams. Error reporting happens by either the client or server sending an ERROR command, and usually the connection will be closed. @@ -32,9 +32,6 @@ Since the protocol is a simple line based, its possible to manually connect to the server using a tool like netcat. A few things should be noted when manually using the protocol: -- When subscribing to a stream using `REPLICATE`, the special token - `NOW` can be used to get all future updates. The special stream name - `ALL` can be used with `NOW` to subscribe to all available streams. - The federation stream is only available if federation sending has been disabled on the main process. - The server will only time connections out that have sent a `PING` @@ -91,9 +88,7 @@ The client: - Sends a `NAME` command, allowing the server to associate a human friendly name with the connection. This is optional. - Sends a `PING` as above -- For each stream the client wishes to subscribe to it sends a - `REPLICATE` with the `stream_name` and token it wants to subscribe - from. +- Sends a `REPLICATE` to get the current position of all streams. - On receipt of a `SERVER` command, checks that the server name matches the expected server name. @@ -140,9 +135,7 @@ the wire: > PING 1490197665618 < NAME synapse.app.appservice < PING 1490197665618 - < REPLICATE events 1 - < REPLICATE backfill 1 - < REPLICATE caches 1 + < REPLICATE > POSITION events 1 > POSITION backfill 1 > POSITION caches 1 @@ -181,9 +174,9 @@ client (C): #### POSITION (S) - The position of the stream has been updated. Sent to the client - after all missing updates for a stream have been sent to the client - and they're now up to date. + On receipt of a POSITION command clients should check if they have missed any + updates, and if so then fetch them out of band. Sent in response to a + REPLICATE command (but can happen at any time). #### ERROR (S, C) @@ -199,24 +192,17 @@ client (C): #### REPLICATE (C) -Asks the server to replicate a given stream. The syntax is: +Asks the server for the current position of all streams. -``` - REPLICATE <stream_name> <token> -``` +#### USER_SYNC (C) -Where `<token>` may be either: - * a numeric stream_id to stream updates since (exclusive) - * `NOW` to stream all subsequent updates. + A user has started or stopped syncing -The `<stream_name>` is the name of a replication stream to subscribe -to (see [here](../synapse/replication/tcp/streams/_base.py) for a list -of streams). It can also be `ALL` to subscribe to all known streams, -in which case the `<token>` must be set to `NOW`. +#### CLEAR_USER_SYNC (C) -#### USER_SYNC (C) + The server should clear all associated user sync data from the worker. - A user has started or stopped syncing + This is used when a worker is shutting down. #### FEDERATION_ACK (C) |