Two settings that decide whether a deployment survives load, neither of which
appeared in any template.
The connection pool. Left unset, Go's defaults apply, and MaxIdleConns is 2:
under load almost every request opens a TCP connection and closes it again,
local ports run out, and the process answers "can't assign requested address"
to everything. Not slower - unavailable. A sweep against MySQL collapsed to
zero successful responses at 64 concurrent requests without these, and served
13,846 req/s with no errors once they were set.
The queue buffer. poolSize is the point at which messages start being dropped,
not a tuning knob: a full queue discards the message and returns an error
rather than blocking, and each stream has one consumer goroutine writing to the
database. At the previous default of 100 a load test lost over 60% of them; at
1000, none. Login and operation logs travel this queue, so what gets lost is
audit data - though only when logger.enableddb is on.
Both carry the reasoning in the file, because the failure mode of each is
invisible until it happens in production.
A rejected request answered 200 with the failure only in the body, so every
layer that reads the status line counted it as served: load balancers, metrics,
client-side retry. A load test against this reported the limiter's own
rejections as successful traffic and overstated throughput more than tenfold.
The threshold was a constant in the middleware, which made 200 QPS the ceiling
of every deployment with nothing in the configuration to reveal it. It now
reads extend.rateLimit.inboundQPS; an absent value keeps 200, so an upgrade
changes nothing, and zero disables the limiter for a deployment behind its own
gateway.
Also drops Strategy: system.BBR. Reading sentinel's source, the adaptive
strategy is consulted only for Load and CpuUsage - for InboundQPS the trigger
count is compared directly - so it read as if the limit adapted to the machine
when it never did.
thirdUpload dispatched on the source parameter and then built the same
zero-value ALiYunOSS in both branches, so source=3 could not have
reached qiniu even with credentials.
Neither branch had credentials to use. OXS.Setup is the initialisation
path and nothing in the repository called it, and no configuration field
existed to fill. The store is now taken from extend.fileStore, and a
provider that was not configured says so rather than producing the
provider's own complaint about an empty bucket name.
The two handlers passed errors.New("") to e.Error, discarding what
actually went wrong; they now pass the error.
The sample had producer/consumer nested keys (streamMaxLength,
approximateMaxLength, visibilityTimeout, bufferSize, concurrency,
blockingTimeout, reclaimInterval) that don't exist on config.RedisQueue —
checked against sdk/config/queue.go, which only reads addr, password, and the
embedded RedisOptions fields, plus group, key_prefix and max_attempts. Filling
in the old sample as written would compile and start fine, since it's YAML
under a key the struct doesn't declare, and every one of those settings would
be silently ignored.
Replaced with the fields the struct actually has. Still commented out —
redis stays opt-in, this only fixes what filling it in would produce.
zhangwenjian