Hi,
regarding #5, since you are talking about startup you mean readiness not
liveness, right? Don’t do it with initialDelaySeconds. Better use startup probe
with combination of failureThreshold and periodsSeconds of, let’s say, 10. This
way you can define *maximum* delay startup time instead of *fixed* startup time.
Also, startup probe should not be larger than critical-analyzer-timeout Artemis
parameter as it comes in play during long startups when large data journal is
loaded. Maybe even look at other parameters of critical analyzer and check if
this doesn’t conflict with other Kubernetes probes.
--
Vilius
From: Shiv Kumar Dixit <[email protected]>
Sent: Tuesday, January 6, 2026 5:59 PM
To: [email protected]
Subject: RE: Artemis broker startup and pending messages impact
Thanks Justin for details.
1. So basically, broker only loads previously active messages (from
../data/journal) in memory on subsequent startups.
2. Messages paged to disk are loaded (from ../data/paging) when previous
queues are empty, and consumers demand more.
3. We export queue size (artemis.persistent.size) per queue via metrics for
monitoring purposes – I assume it is sum of all pending messages on a given
queue (journal + paging + large-messages). Is this correct?
4. Is it correct to assume that total messages which are in ../data/journal
folder and expected to be loaded into memory on subsequent startup is
restricted by global-max-size param in heap. E.g. if my max heap is 6 GB and
global-max-size is set to 1.2 GB then broker can hold max 1.2 GB of messages in
memory (loaded via ../data/journal) and rest pending messages will be paged.
5. When we deploy broker in K8s, it also needs a liveness probe to indicate
broker has started successfully. It means by this time all required messages
etc. should be loaded from journal. Is there a guideline for the
initialDelaySeconds that we should set for liveness probe in K8s? If it is too
early then broker startup is not done fully and we risk restarts. If it is too
late, we wait unnecessary for the first check to be triggered.
Best Regards
Shiv
From: Justin Bertram <[email protected]<mailto:[email protected]>>
Sent: 06 January 2026 08:14 PM
To: [email protected]<mailto:[email protected]>
Subject: Re: Artemis broker startup and pending messages impact
Unverified Sender: The sender of this email has not been verified. Review the
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> When artemis broker starts up, does it need to first load all persistent
> messages in memory to be ready for normal broker operations?
Among other things, the broker will parse and load messages persisted to the
journal. However, it won't parse and load messages persisted to paging. Pages
aren't parsed until the queue is empty and more messages are needed.
In general, you can think of the journal as an up-to-date snapshot of what is
in the heap. It includes address & queue definitions, messages, transaction
meta-data, duplicate ID caches, etc.
> if we stop broker with viz. 4 GB of persistent pending messages, does it need
> min 4 GB of free memory at startup to load these messages?
If you stop the broker with 4GB of persistent pending messages then after you
restart the broker and reload the messages you'll have that same 4GB of
persistent pending messages.
> If it uses heap memory for this work or non-heap memory is used for this?
It uses heap.
I think I answered #3 in the answer to #1 above.
> If a message is of 10KB, does broker need exact 10KB to store the messages in
> memory and disk? Or additional space is needed for metadata or encoding etc.?
There's always some additional space required for metadata, etc.
Justin
On Tue, Jan 6, 2026 at 5:09 AM Shiv Kumar Dixit
<[email protected]<mailto:[email protected]>>
wrote:
We are hosting Artemis broker in Kubernetes using operator-based solution. We
deploy the broker as statefulset with 2 or 4 replicas. We assign for e.g. 6 GB
for heap and 9 GB for pod, 1.2 GB (1/5 of max heap) for global-max-size. All
addresses normally use -1 for max-size-bytes but some less frequently used
queues are defined with 100KB for max-size-bytes to allow early paging.
We need some information or documentation link to address following queries.
1. When artemis broker starts up, does it need to first load all persistent
messages in memory to be ready for normal broker operations? E.g. if we stop
broker with viz. 4 GB of persistent pending messages, does it need min 4 GB of
free memory at startup to load these messages?
2. If it uses heap memory for this work or non-heap memory is used for this?
3. If we have defined global-max-size of 1.2 GB and address-full-policy is PAGE
and broker has 4 GB of persistent pending messages, will broker first load 1.2
GB of messages in memory from all addresses for faster delivery and rest
messages will remains on disk? Or first all messages must be loaded in memory
and then paging starts afterwards by keeping 1.2 GB in memory and pushing rest
to disk again?
4. If a message is of 10KB, does broker need exact 10KB to store the messages
in memory and disk? Or additional space is needed for metadata or encoding etc.?
Best Regards,
Shiv
