Handles a connection from a client to Spanner. This ConnectionHandler uses WireMessage to receive and send all messages from and to the client, using the intermediate
representation IntermediateStatement that servers as a middle layer between Postgres and
Spanner.
Each ConnectionHandler is also a Thread. Although a TCP connection does not
necessarily need to have its own thread, this makes the implementation more straightforward.
Add a currently executing statement to a buffer. This is only used in case a statement in
flight is cancelled. It must be saved separately, as a new connection is spawned to issue a
cancellation (as per Postgres protocol standard). This means some sort of IPC is required,
which in this case is a global Map.
To be used by a cancellation command to cancel a currently running statement, as contained in a
specific connection identified by connectionId. Since cancellation is a flimsy contract at
best, it is not imperative that the cancellation run, but it should be attempted nonetheless.
Returns the number of invalid messages that this connection has received in a row. This can for
example happen if a client has initiated a COPY operation and the copy operation fails on the
server. The server will then respond with an error response, but if the client fails to read
that message and continues to send copy data messages, the server could get flooded. This value
is used to detect such a situation and breaks the connection if too many invalid messages in a
row are received.
Reads and handles wire-protocol messages. This method is normally only called from this ConnectionHandler, but certain sub-protocols such as the COPY protocol also need to process
messages in line.
Simple runner starts a loop which keeps taking inbound messages, processing them, sending them
to Spanner, getting a result, processing that result, and replying to the client (in that
order). Also instantiates input and output streams from the client and handles auth.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2024-11-06 UTC."],[],[]]
