| --- |
| { |
| "title": "Use FE profiler to generate flame graph", |
| "language": "en" |
| } |
| --- |
| |
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| |
| # introduce |
| In versions 2.1.4 and above of Doris, there will be a `profile_fe.sh` script in the fe deployment directory `${DORIS_FE_HOME}/bin`. This script can use the async-profiler tool to generate a flame graph of fe, which can be used to identify the bottleneck points of fe. |
| |
| :::note |
| Note: The async profiler tool currently only supports Linux and MacOS systems, and does not currently support Windows systems |
| ::: |
| |
| The usage cases are as follows |
| ```shell |
| $ # By default, monitor FE for 10 seconds to generate a flame graph |
| $ ${DORIS_FE_HOME}/bin/profile_fe.sh |
| |
| $ # Set listening fe for 30 seconds to generate a flame graph |
| $ PROFILE_SECONDS=30 ${DORIS_FE_HOME}/bin/profile_fe.sh |
| ``` |
| |
| After running the above command, it will listen to fe for a period of time. During this period, we need to repeatedly send key queries to this FE so that the async-profiler can collect FE's key stack frame information. |
| After collecting stack frame information, the script will generate an HTML flame graph file in the `${DORIS_FE_HOME}/log` directory. Generally, the bottleneck of fe will appear as a flat top (short and wide) in the flame graph. We can optimize the performance of the code corresponding to these stack frames. |
| |
| The following is an example of a flame graph |
|  |
| |
| # Using async-profiler in lower versions of fe |
| In versions below 2.1.4, two files need to be manually downloaded |
| 1. Download [ap-loader-all-3.0-8.jar](https://repo1.maven.org/maven2/me/bechberger/ap-loader-all/3.0-8/ap-loader-all-3.0-8.jar) to the `${DORIS_FE_HOME}/lib`directory |
| 2. Download [profile_fe.sh](https://raw.githubusercontent.com/apache/doris/master/bin/profile_fe.sh) to the `${DORIS_FE_HOME}/bin`directory |
| 3. Just run `profile_fe.sh` |
