Very slow artifact publishing

Hi Linus,

Were you experiencing the slow artifact publishing previously, or were there any recent changes that might have resulted in this problem? 

Did you also check for possible network-related issues? It is possible such issues are caused by network components such as antivirus/firewall/proxy on the server or between the server and the agents. If you did not check for this possibility, you can try to disable or bypass them and check the performance again before continuing troubleshooting.

If that does not help, please enable debug logging on the agent, and reproduce the issue and share the teamcity-agent.log together with the build log and the teamcity-server.log covering the same time period via our secure upload service:

https://uploads.jetbrains.com/

There is a possible workaround: TeamCity offers the ability to modify the buffer sizes for both sending and receiving, and it can be done by setting the following properties in the <agent_home>/conf/buildAgent.properties file:

teamcity.httpClient.connection.http.socket.sendbuffer=xxx
teamcity.httpClient.connection.http.socket.receivebuffer=xxx

 
Perhaps you can try to tweak these settings in your build agents and check if it helps.

Hi,
We've tried this but notice no difference. We still see very slow artifact uploading speeds:
Will publish 1 artifact(s) to TeamCity node with id MAIN_SERVER

Hi,

Will publish 1 artifact(s) to TeamCity node with id MAIN_SERVER

Perhaps you were trying to share more information and something went wrong? 

Is it possible that you are using an old java version in your TeamCity Server or in your build agents? As mentioned in the following comment of another post, there are reported cases in which this was causing slow artifact uploads: 

https://teamcity-support.jetbrains.com/hc/en-us/community/posts/360000297579-Publish-Artifacts-and-REALLY-REALLY-slow?page=1#community_comment_360001664799

You can also try to use the following small utility that can test the artifact upload in a bare-bones scenario: https://github.com/tolache/artifact-upload-demo 

This utility runs the Tomcat server and then uploads a file to it. You can try to use it and measure how long it takes to upload the same file and compare it with TeamCity. If it is faster, there is probably something wrong on the TeamCity side, but if the speed is the same, it might be something with Tomcat. 

Please let me know your findings.

Thanks

Hi, 

We have the same issue. 

The upload of artifacts (artifact size ~11GB) takes more than 10 minutes.  

To make sure there is no problem with infrastructure, we have tried to upload the very same artifact as a build step by simply copying it to the same location. This takes less than 20 seconds. 

The download of artifacts is extremely slow, too. Even on the TeamCity server itself, the download speed is 10MB/s on a good day and can go to the KB/s.

Java version: 17.0.10

Java VM info: OpenJDK 64-Bit Server VM

Java Home path: c:\TeamCity\jre

Server: Apache Tomcat/9.0.96

Thanks

Igor  

Hi Igor,

Which TeamCity version are you currently using? Did any of the suggestions from above help you with this issue? You can try also try to change the TeamCity server logging preset to debug-artifacts , reproduce the issue and share the teamcity-server.log* files with us via our secure upload service:
https://uploads.jetbrains.com/

If you do it, please share the resulting upload ID with us. After you are done reproducing the issue, remember to set the default logging preset again.

Thanks,

Guilherme

We run  TeamCity Enterprise 2024.12 (build 174331)

Upload ID: 2025_07_29_eS28DzDmN3YRm39dfvbd5H 

Thanks 

igor

To add some information. 

In the attached build log, you can see that publishing takes ~10 minutes. 

If  we do “publishing” as  a  build step, just run copy to  the same  location, it takes  ~20sec 

We publish right to the TC server 

If we try to set the UNC location to the network storage , the publishing will take even longer. And again - copying to the same location will take just a few seconds. 

Hi Igor,

The issue you are experiencing is a known issue caused by slow artifact compression:
TW-74758

Please follow the issue for updates. We also recommend you vote for it.

Can you please check if the following workaround helps?
https://youtrack.jetbrains.com/issue/TW-74758/Slow-Zip-artifact-compression#focus=Comments-27-5721135.0-0

We have got the same problem, artifacts download speed is fast but publishing the artifacts through the HTTP webpublisher server is very slow. I have ran an iperf3 test between the Teamcity agent and the Teamcity Server and the results are good, however publishing the artifacts upload speed is very poor. Artifacts are stored in a 3TB SSD drive
We are running TeamCity Enterprise 2025.07.2 Build 197379 under a docker container through network host
TeamCity Agent JDK version the 21.0.7

Here is an example of how slow the downloading of artifacts from the server is:

from build log 

HTTP transport has processed 595 files (total size: 10.01 GB, average download speed: 3.4 MB/s)   

To make sure the problem is  not the infrastructure, I did test -  run regular copy from the very same location on the Teamcity server to the same agent 

 about infrastructure:

All run on VMware. The server and agents are hosted on a dedicated VLAN, no AV,  no routing, no ACL.  

Hi Igor,

Did you try the workaround mentioned in my previous comment?

Thanks,

Guilherme

The workaround has nothing to do with downloading. It suggests using an external zip tool,  which we already do.  

The answer - it does not help.

Hi Igor,

Could you please capture a set of server thread dumps during slow artifact publishing? 
 
You can make the server save 60 thread dumps with a 1-second interval by adding the below records to your internal properties. The server will start making the thread dumps as soon as you add the properties.
 

teamcity.diagnostics.periodicThreadDumps.name=automatic_batch
teamcity.diagnostics.periodicThreadDumps.count=60
teamcity.diagnostics.periodicThreadDumps.period.ms=1000

 
Please share also the corresponding teamcity-server.log* files with us. You can share the resulting files with us via our secure upload service:
https://uploads.jetbrains.com/

Please share the resulting upload id here in this thread so that we can investigate further.

Thanks,

Guilherme

uploaded 

Upload id: 2025_10_31_27S6yWuuXbuN8MV2tCfyed (files: threadDumps-2025-10-31.zip, teamcity-server.log)