Elasticsearch runs on my low-configured system with 4G memory and four cores. I have a problem with high CPU usage with ES. Even after closing the analyzer (s), reduce the thread size, etc.
While analyzing the situation, I got a stack trace for Elasticsearch and I see hundreds of threads, it is determined by the NP configuration, but only some of them work, and only one thread has a large percentage of CPU time.
Here is the stack trace:
top - 09:51:44 up 1 day, 1:46, 2 users, load average: 4.94, 5.35, 5.29 Tasks: 684 total, 2 running, 682 sleeping, 0 stopped, 0 zombie Cpu(s): 7.2%us, 1.1%sy, 0.8%ni, 83.7%id, 6.7%wa, 0.1%hi, 0.4%si, 0.0%st Mem: 4043340k total, 3466748k used, 576592k free, 30272k buffers Swap: 4192960k total, 410704k used, 3782256k free, 465868k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 25134 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25136 root 20 0 1086m 978m 14m S 0.0 24.8 0:03.34 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25137 root 20 0 1086m 978m 14m S 0.0 24.8 6:43.82 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25138 root 20 0 1086m 978m 14m S 0.0 24.8 6:43.17 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25139 root 20 0 1086m 978m 14m S 0.0 24.8 6:43.05 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25140 root 20 0 1086m 978m 14m S 0.0 24.8 6:40.66 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25141 root 20 0 1086m 978m 14m S 15.3 24.8 204:53.20 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25143 root 20 0 1086m 978m 14m S 0.0 24.8 10:47.46 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25144 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.37 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25145 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.04 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25146 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.20 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25147 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25148 root 20 0 1086m 978m 14m S 0.0 24.8 0:19.46 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25149 root 20 0 1086m 978m 14m S 0.0 24.8 0:24.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25150 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25151 root 20 0 1086m 978m 14m S 0.0 24.8 0:16.63 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25156 root 20 0 1086m 978m 14m S 0.0 24.8 0:03.07 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25159 root 20 0 1086m 978m 14m S 0.3 24.8 3:46.78 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25201 root 20 0 1086m 978m 14m S 0.0 24.8 0:01.07 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25202 root 20 0 1086m 978m 14m S 0.0 24.8 0:01.16 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25205 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25206 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25207 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25208 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.52 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25209 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.56 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25210 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25211 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25212 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.53 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25213 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25214 root 20 0 1086m 978m 14m S 0.0 24.8 0:02.74 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25215 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25216 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25217 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25218 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25219 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25220 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.54 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25221 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.52 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25222 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.55 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25223 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25233 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25241 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25245 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25249 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25252 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25259 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.00 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25264 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.24 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25266 root 20 0 1086m 978m 14m S 0.7 24.8 0:40.80 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25269 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.44 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25276 root 20 0 1086m 978m 14m S 0.0 24.8 0:37.28 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25278 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.80 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25280 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.04 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25318 root 20 0 1086m 978m 14m S 0.0 24.8 0:15.87 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25329 root 20 0 1086m 978m 14m S 0.0 24.8 0:09.73 /usr/bin/java -Xms808m -Xmx808m -Xss256k 25333 root 20 0 1086m 978m 14m S 0.0 24.8 0:00.01 /usr/bin/java -Xms808m -Xmx808m -Xss256k
As it seems on the code block, the stream with the identifier 25141 has much more than others, and some of them were not used at least once.
Why is this happening and what should I do to prevent high CPU usage.