Hi Mark, In the newly opened bug report about this (https://bz.apache.org/bugzilla/show_bug.cgi?id=65773), you noted that logging at level FINE would show what is happening.
What exactly are we looking at when it says it “Swallowed [0] bytes”? I can get more data, but at this point, I just want to understand the log sample: Time: 2022-01-12 03:44:42.895, Level: FINE, Logger: org.apache.coyote.http2.Http2Parser org.apache.coyote.http2.Http2Parser swallow - Connection [54], Stream [2076417], Swallowed [0] bytes Best Regards, -- Doug Whitfield | Enterprise Architect, OpenLogic<https://www.openlogic.com/?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> Perforce Software<http://www.perforce.com/?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> Visit us on: LinkedIn<https://www.linkedin.com/company/perforce?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> | Twitter<https://twitter.com/perforce?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> | Facebook<https://www.facebook.com/perforce/?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> | YouTube<https://www.youtube.com/user/perforcesoftware?utm_leadsource=email-signature&utm_source=outlook-direct-email&utm_medium=email&utm_campaign=2019-common&utm_content=email-signature-link> From: Mark Thomas <ma...@apache.org> Date: Monday, January 10, 2022 at 1:52 AM To: users@tomcat.apache.org <users@tomcat.apache.org> Subject: Re: HTTP2 : WINDOW_UPDATE not sent on stream level On 10/01/2022 07:23, Arshiya Shariff wrote: > Thank you for the response Mark . > > Yes, with the default window size the requests process fine . > > We were just attempting to reproduce the original issue that we are facing in > production with version 9.0.38 where few connections go unresponsive for few > seconds around the same time i.e. tomcat is able to receive the > headers/partial data, but not responding back with window_update or sending > ping frames and then after sometime tomcat sends PING frame and the > connection processes further requests successfully . The GC looks fine at > that time. > > Could there be any reasons that can cause this ? Please let us know. The behaviour you saw with 9.0.38 is likely to be a known bug that is fixed in 9.0.56. From the changelog: https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fbz.apache.org%2Fbugzilla%2Fshow_bug.cgi%3Fid%3D65179&data=04%7C01%7Cdwhitfield%40perforce.com%7C8c32c6efff5f492ddb9e08d9d40e1007%7C95b666d19a7549ab95a38969fbcdc08c%7C0%7C0%7C637773979411880749%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=yQG8pgfLrw6ED9tbG5m5JvKuhEljcsIC4RpvIqmPEl8%3D&reserved=0 Ensure that the connection level flow control window from the client to the server is updated when handling DATA frames received for completed streams else the flow control window may become exhausted. It could also be: Correct bugs in the HTTP/2 connection flow control management that meant it was possible for a connection to stall waiting for a connection flow control window update that had already arrived. Any streams on that connection that were trying to write when this happened would time out. I think the first entry is more likely but it could be either. If you want to be reasonably sure which it is, test with versions 9.0.44, 9.0.45, 9.0.48 and 9.0.50. If you want to be really sure, build Tomcat from source for the commits just before and just after each fix and test with those builds. Mark This e-mail may contain information that is privileged or confidential. If you are not the intended recipient, please delete the e-mail and any attachments and notify us immediately.
