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Diffstat (limited to 'doc/administration/database_load_balancing.md')
-rw-r--r-- | doc/administration/database_load_balancing.md | 29 |
1 files changed, 13 insertions, 16 deletions
diff --git a/doc/administration/database_load_balancing.md b/doc/administration/database_load_balancing.md index 64eca0b00f6..50ccebffe73 100644 --- a/doc/administration/database_load_balancing.md +++ b/doc/administration/database_load_balancing.md @@ -212,28 +212,25 @@ without it immediately leading to errors being presented to the users. ## Logging -The load balancer logs various messages, such as: +The load balancer logs various events in +[`database_load_balancing.log`](logs.md#database_load_balancinglog-premium-only), such as - When a host is marked as offline - When a host comes back online - When all secondaries are offline +- When a read is retried on a different host due to a query conflict -Each log message contains the tag `[DB-LB]` to make searching/filtering of such -log entries easier. For example: +The log is structured with each entry a JSON object containing at least: -``` -[DB-LB] Host 10.123.2.5 came back online -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Host 10.123.2.6 came back online -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Marking host 10.123.2.7 as offline -[DB-LB] Host 10.123.2.7 came back online -[DB-LB] Host 10.123.2.7 came back online +- An `event` field useful for filtering. +- A human-readable `message` field. +- Some event-specific metadata. For example, `db_host` +- Contextual information that is always logged. For example, `severity` and `time`. + +For example: + +```json +{"severity":"INFO","time":"2019-09-02T12:12:01.728Z","correlation_id":"abcdefg","event":"host_online","message":"Host came back online","db_host":"111.222.333.444","db_port":null,"tag":"rails.database_load_balancing","environment":"production","hostname":"web-example-1","fqdn":"gitlab.example.com","path":null,"params":null} ``` ## Handling Stale Reads |