Current Behavior

Obvious memory leak when the weight sum of all nodes in the upstream of the chash type is large

Expected Behavior

smooth memory usage

Error Logs

Memory information of the production environment, captured using the openresty xray tool

Steps to Reproduce

1. change worker_processes to 1 for easy observation
2. create upstream
   curl "127.0.0.1:9080/apisix/admin/upstreams" -XPOST -H"x_api_key:edd1c9f034335f136f87ad84b625c8f1" -d '
   {
   "type": "chash",
   "key": "chash-key",
   "retries": 0,
   "name": "stress_apisix-memory-test_28002",
   "desc": "stress_apisix-memory-test_28002",
   "hash_on": "header",
   "timeout": {
   "send": 0.1,
   "connect": 0.1,
   "read": 0.1
   },
   "nodes": [
   {
   "port": 28002,
   "weight": 5000,
   "host": "192.168.0.1"
   },
   {
   "port": 28002,
   "weight": 5000,
   "host": "192.168.0.2"
   }
   ]
   }
   '
3. create route
   curl "127.0.0.1:9080/apisix/admin/routes" -XPOST -H"x_api_key:edd1c9f034335f136f87ad84b625c8f1" -d '
   {
   "upstream_id": "the upstream id created in step 2",
   "hosts": [
   "sc.test.com"
   ],
   "uris": [
   "/mem/test"
   ],
   "name": "duisys>apisix-memory-test>prod",
   "desc": "duisys>apisix-memory-test>prod"
   }
   '
4. run below command
   for((i=1;i<100;i++)); do
   curl "127.0.0.1:9080/apisix/admin/upstreams/{the upstream id created in step 2}" -XPATCH -H"x_api_key:edd1c9f034335f136f87ad84b625c8f1" -d '
   {
   "desc": "stress_apisix-memory-test_28002"
   }
   ' > /dev/null 2>&1 ;
   curl "127.0.0.1:9080/mem/test" -H"host:sc.test.com" > /dev/null 2>&1;
   done
5. the memory cost of worker is up to 1.2GB
   

Environment

• APISIX version :2.13.1
• Operating system:Linux 3.10.0-693.el7.x86_64 change: added doc of how to load plugin. #1 SMP Tue Aug 22 21:09:27 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
• OpenResty:
  nginx version: openresty/1.19.9.1
  built by gcc 9.3.1 20200408 (Red Hat 9.3.1-2) (GCC)
  built with OpenSSL 1.1.1n 15 Mar 2022
  TLS SNI support enabled
  configure arguments: --prefix=/usr/local/openresty/nginx --with-cc-opt='-O2 -DAPISIX_BASE_VER=1.19.9.1.5 -DNGX_LUA_ABORT_AT_PANIC -I/usr/local/openresty/zlib/include -I/usr/local/openresty/pcre/include -I/usr/local/openresty/openssl111/include' --add-module=../ngx_devel_kit-0.3.1 --add-module=../echo-nginx-module-0.62 --add-module=../xss-nginx-module-0.06 --add-module=../ngx_coolkit-0.2 --add-module=../set-misc-nginx-module-0.32 --add-module=../form-input-nginx-module-0.12 --add-module=../encrypted-session-nginx-module-0.08 --add-module=../srcache-nginx-module-0.32 --add-module=../ngx_lua-0.10.20 --add-module=../ngx_lua_upstream-0.07 --add-module=../headers-more-nginx-module-0.33 --add-module=../array-var-nginx-module-0.05 --add-module=../memc-nginx-module-0.19 --add-module=../redis2-nginx-module-0.15 --add-module=../redis-nginx-module-0.3.7 --add-module=../ngx_stream_lua-0.0.10 --with-ld-opt='-Wl,-rpath,/usr/local/openresty/luajit/lib -Wl,-rpath,/usr/local/openresty/wasmtime-c-api/lib -L/usr/local/openresty/zlib/lib -L/usr/local/openresty/pcre/lib -L/usr/local/openresty/openssl111/lib -Wl,-rpath,/usr/local/openresty/zlib/lib:/usr/local/openresty/pcre/lib:/usr/local/openresty/openssl111/lib' --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../mod_dubbo --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../ngx_multi_upstream_module --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../apisix-nginx-module --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../apisix-nginx-module/src/stream --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../wasm-nginx-module --add-module=/tmp/tmp.HOhTx9UT8p/openresty-1.19.9.1/../lua-var-nginx-module --with-poll_module --with-pcre-jit --with-stream --with-stream_ssl_module --with-stream_ssl_preread_module --with-http_v2_module --without-mail_pop3_module --without-mail_imap_module --without-mail_smtp_module --with-http_stub_status_module --with-http_realip_module --with-http_addition_module --with-http_auth_request_module --with-http_secure_link_module --with-http_random_index_module --with-http_gzip_static_module --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-threads --with-compat --with-stream --with-http_ssl_module
• etcd version: 3.5.0