confluence server download attachment by restful api make server no response

Normal Test User

version: confluence server 6.15.2

server: 16c64g

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there is my config

CATALINA_OPTS="-XX:-PrintGCDetails -XX:+PrintGCDateStamps -XX:-PrintTenuringDistribution ${CATALINA_OPTS}" CATALINA_OPTS="-Xloggc:$LOGBASEABS/logs/gc-`date +%F_%H-%M-%S`.log -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=5 -XX:GCLogFileSize=2M ${CATALINA_OPTS}" CATALINA_OPTS="-XX:G1ReservePercent=20 ${CATALINA_OPTS}" CATALINA_OPTS="-Djava.awt.headless=true ${CATALINA_OPTS}" CATALINA_OPTS="-Datlassian.plugins.enable.wait=300 ${CATALINA_OPTS}" CATALINA_OPTS="-Xms38g -Xmx38g -XX:+UseG1GC ${CATALINA_OPTS}" CATALINA_OPTS="-Dsynchrony.enable.xhr.fallback=true ${CATALINA_OPTS}" CATALINA_OPTS="-Dorg.apache.tomcat.websocket.DEFAULT_BUFFER_SIZE=32768 ${CATALINA_OPTS}" CATALINA_OPTS="${START_CONFLUENCE_JAVA_OPTS} ${CATALINA_OPTS}" CATALINA_OPTS="-Dconfluence.context.path=${CONFLUENCE_CONTEXT_PATH} ${CATALINA_OPTS}" CATALINA_OPTS="-XX:ReservedCodeCacheSize=512m -XX:+UseCodeCacheFlushing -Djava.security.egd=file:/dev/./urandom ${CATALINA_OPTS}" CATALINA_OPTS="-Dsynchrony.memory.max=8g ${CATALINA_OPTS}"

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this are some gclog

2023-06-20T13:31:28.598+0800: 307048.578: [GC pause (G1 Evacuation Pause) (young) 25G->3251M(38G), 0.1757711 secs] 2023-06-20T13:33:47.798+0800: 307187.779: [GC pause (G1 Evacuation Pause) (young) 25G->3291M(38G), 0.1945276 secs] 2023-06-20T13:36:28.409+0800: 307348.389: [GC pause (G1 Evacuation Pause) (young) 25G->3298M(38G), 0.1882822 secs] 2023-06-20T13:39:01.047+0800: 307501.027: [GC pause (G1 Evacuation Pause) (young) 25G->3348M(38G), 0.1651067 secs] 2023-06-20T13:41:26.506+0800: 307646.486: [GC pause (G1 Evacuation Pause) (young) 25G->3473M(38G), 0.1817582 secs] 2023-06-20T13:44:33.583+0800: 307833.564: [GC pause (G1 Evacuation Pause) (young) 25G->3365M(38G), 0.1917491 secs] 2023-06-20T13:47:58.989+0800: 308038.969: [GC pause (G1 Evacuation Pause) (young) 25G->3408M(38G), 0.1935316 secs] 2023-06-20T13:50:17.290+0800: 308177.270: [GC pause (G1 Evacuation Pause) (young) 23G->3443M(38G), 0.1761307 secs] 2023-06-20T13:53:28.988+0800: 308368.968: [GC pause (G1 Evacuation Pause) (young) 25G->3470M(38G), 0.1919880 secs] 2023-06-20T13:55:52.826+0800: 308512.807: [GC pause (GCLocker Initiated GC) (young) 25G->3561M(38G), 0.2116989 secs] 2023-06-20T13:56:22.383+0800: 308542.364: [GC pause (G1 Evacuation Pause) (young) 21G->3563M(38G), 0.1937941 secs] 2023-06-20T13:57:45.395+0800: 308625.376: [GC pause (G1 Evacuation Pause) (young) 18G->3628M(38G), 0.1896990 secs] 2023-06-20T13:59:26.752+0800: 308726.733: [GC pause (G1 Evacuation Pause) (young) 15G->3558M(38G), 0.1703195 secs] 2023-06-20T14:00:26.915+0800: 308786.895: [GC pause (G1 Evacuation Pause) (young) 12G->3561M(38G), 0.1709033 secs]

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there are catalina.out

19-Jun-2023 10:12:07.831 WARNING [ContainerBackgroundProcessor[StandardEngine[Standalone]]] org.apache.catalina.valves.StuckThreadDetectionValve.notifyStuckThreadDetected Thread [http-nio-8090-exec-46] (id=[465]) has been active for [67,753] milliseconds (since [6/19/23 10:11 AM]) to serve the same request for [https://xxx/download/attachments/xxx&api=v2] and may be stuck (configured threshold for this StuckThreadDetectionValve is [60] seconds). There is/are [6] thread(s) in total that are monitored by this Valve and may be stuck.

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i have many attachment to download

why download attachment by api make server no response,  and how can i fix it?