synapse/docs/usage/administration/request_log.md

Request log format

HTTP request logs are written by synapse (see site.py for details).

See the following for how to decode the dense data available from the default logging configuration.

2020-10-01 12:00:00,000 - synapse.access.http.8008 - 311 - INFO - PUT-1000- 192.168.0.1 - 8008 - {another-matrix-server.com} Processed request: 0.100sec/-0.000sec (0.000sec, 0.000sec) (0.001sec/0.090sec/3) 11B !200 "PUT /_matrix/federation/v1/send/1600000000000 HTTP/1.1" "Synapse/1.20.1" [0 dbevts]
-AAAAAAAAAAAAAAAAAAAAA-   -BBBBBBBBBBBBBBBBBBBBBB-   -C-   -DD-   -EEEEEE-  -FFFFFFFFF-   -GG-    -HHHHHHHHHHHHHHHHHHHHHHH-                     -IIIIII- -JJJJJJJ-  -KKKKKK-, -LLLLLL-  -MMMMMMM- -NNNNNN- O  -P- -QQ-  -RRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR-   -SSSSSSSSSSSS-   -TTTTTT-

Part	Explanation
AAAA	Timestamp request was logged (not received)
BBBB	Logger name (synapse.access.(http|https).<tag>, where 'tag' is defined in the listeners config section, normally the port)
CCCC	Line number in code
DDDD	Log Level
EEEE	Request Identifier (This identifier is shared by related log lines)
FFFF	Source IP (Or X-Forwarded-For if enabled)
GGGG	Server Port
HHHH	Federated Server or Local User making request (blank if unauthenticated or not supplied). If this is of the form `@aaa:example.com
IIII	Total Time to process the request
JJJJ	Time to send response over network once generated (this may be negative if the socket is closed before the response is generated)
KKKK	Userland CPU time
LLLL	System CPU time
MMMM	Total time waiting for a free DB connection from the pool across all parallel DB work from this request
NNNN	Total time waiting for response to DB queries across all parallel DB work from this request
OOOO	Count of DB transactions performed
PPPP	Response body size
QQQQ	Response status code Suffixed with ! if the socket was closed before the response was generated. A 499! status code indicates that Synapse also cancelled request processing after the socket was closed.
RRRR	Request
SSSS	User-agent
TTTT	Events fetched from DB to service this request (note that this does not include events fetched from the cache)

MMMM / NNNN can be greater than IIII if there are multiple slow database queries running in parallel.

Some actions can result in multiple identical http requests, which will return the same data, but only the first request will report time/transactions in KKKK/LLLL/MMMM/NNNN/OOOO - the others will be awaiting the first query to return a response and will simultaneously return with the first request, but with very small processing times.