如何使用gprof对程序进行性能分析

2024-06-22 22:52

本文主要是介绍如何使用gprof对程序进行性能分析,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!

如何使用gprof对程序进行性能分析


目录

1 gprof概述
2 gprof原理简述
3 gprof使用
  3.1 gprof使用简述
  3.2 gprof使用示例
4 小结


1 gprof概述

    gprof 是 一个 GNU 的程序性能分析工具,可以用于分析C\C++程序的执行性能。gprof工具可以统计出各个函数的调用次数、执行时间、函数调用关系,具体功能可以通过 man gprof进一步了解。通常该工具在大多数linux内核的发行版本中会在你安装C/C++编译器的同时默认安装上。


2 gprof原理简述

    通过在编译、链接的时候使用 -pg 选项,就能够控制gcc/g++ 编译器在程序的每个函数中插入插桩函数,从而跟踪目标函数的执行时间、调用关系(通过函数调用堆栈查找)、执行次数等信息,并将相关数据保存到 gmon.out 文件中。

    【注意】: 必须是编译链接的时候都要添加 -pg 参数。并且目标程序不能使用 strip 命令去除符号表,否则 gprof 工具无法正常处理 gmon.out 到 profile.txt文件。


3 gprof使用

3.1 gprof使用简述

a、 在编译、链接设置中开启 -pg 参数:

    使用cmake,在CMakeList.txt中添加

SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pg")
SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pg")
SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -pg")
SET(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} -pg")

    使用make,在Makefile中设置

CFLAGS += -pg
CPPFLAGS += -pg
LDFLAGS += -pg

b、 编译后正常运行程序

.testApp arg1 arg2

【注意】 运行程序后,要程序正常退出,才能正常生成 gmon.out 文件;在此步骤中程序是可以带命令行参数执行的。

c、 分析、收集数据

gprof testApp gmon.out > profile.txt

【注意】 在此步骤中,目标程序如果是带参的,此步骤不可以填入命令行参数。

d、 分析数据图形化

gprof2dot -e0 -n0 profile.txt > profile.dot
dot profile.dot -Tpng -o profile.png

【说明】 在此步骤中,需要通过 gprof2dot 和 dot工具将结果图形化,方便查看。

3.2 gprof使用示例

上一小节简单讲述了如何 gprof 的使用,本小节会以 s_log_safe开源项目 为实例,介绍如何使用 gprof 工具 进行性能分析。

a、 clone s_log_safe项目源码

git clone https://github.com/smallerxuan/s_log_safe.gitcd s_log_safetree

clone完成后进入路径,能看到如下的目录结构:

在这里插入图片描述

b、 修改Makefile文件

gedit ./Makefile

用编辑器打开 Makefile文件,修改 FLAGS_BASE 关闭O2优化,添加 -pg 选项;给 LDFLAGS 追加 -pg;注释 strip 调用。

在这里插入图片描述

在这里插入图片描述
在这里插入图片描述

c、 调整测试用例并编译项目

gedit ./main.c

用编辑器打开 main.c 文件,对测试程序进行简单修改,不然测试程序不会自然结束。

#include <stdio.h>
#include "s_log_safe.h"static int test_mark = 8;void* thread_1_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_1", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_a("%s %d","测试1",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_2_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_2", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_v("%s %d","测试2",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_3_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_3", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_e("%s %d","测试3",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_4_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_4", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_w("%s %d","测试4",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_5_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_5", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_t("%s %d","测试5",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_6_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_6", S_LOG_SAFE_OPT_DEBUG);do {s_log_safe_i("%s %d","测试6",*count);usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_7_exec(void* arg)
{int* count =  (int*)arg;s_safe_tag("thread_7", S_LOG_SAFE_OPT_TRACE);do {s_log_safe_d("%s %d","测试7",*count);if((*count)%8 == 0) {s_safe_tag_log_level_limit_set(S_LOG_SAFE_OPT_DEBUG);} else {s_safe_tag_log_level_limit_set(S_LOG_SAFE_OPT_TRACE);}usleep(5000);} while (*count -= 1);test_mark -= 1;return s_log_safe_null;
}void* thread_main_exec(void* arg)
{int count = 0;unsigned int log_safe_pool_cap = 0;unsigned int log_safe_pool_used = 0;s_safe_tag("main", S_LOG_SAFE_OPT_DEBUG);log_safe_pool_cap = s_log_safe_output_pool_cap_get();while(test_mark > 1) {log_safe_pool_used = s_log_safe_output_pool_used_get();s_log_safe_i("%s log_safe_pool_cap:%d log_safe_pool_used:%d count:%d","main", log_safe_pool_cap, log_safe_pool_used, count++);usleep(5000);}test_mark -= 1;return s_log_safe_null;
}int main(void)
{int                  ret = 0;s_log_safe_thread_t* s_log_safe_thread_1_p;s_log_safe_thread_t* s_log_safe_thread_2_p;s_log_safe_thread_t* s_log_safe_thread_3_p;s_log_safe_thread_t* s_log_safe_thread_4_p;s_log_safe_thread_t* s_log_safe_thread_5_p;s_log_safe_thread_t* s_log_safe_thread_6_p;s_log_safe_thread_t* s_log_safe_thread_7_p;s_log_safe_thread_t* s_log_safe_thread_main_p;int                  count_1 = 77;int                  count_2 = 66;int                  count_3 = 55;int                  count_4 = 44;int                  count_5 = 33;int                  count_6 = 22;int                  count_7 = 11;ret = s_log_safe_init();if(ret != 0) {return 0;}s_log_safe_thread_7_p = s_log_safe_thread_create(thread_main_exec, (void*)s_log_safe_null, "", S_LOG_SAFE_THREAD_PRIORITY, 1024);s_log_safe_thread_1_p = s_log_safe_thread_create(thread_1_exec, (void*)&count_1, "", 10, 1024);s_log_safe_thread_2_p = s_log_safe_thread_create(thread_2_exec, (void*)&count_2, "", 10, 1024);s_log_safe_thread_3_p = s_log_safe_thread_create(thread_3_exec, (void*)&count_3, "", 12, 1024);s_log_safe_thread_4_p = s_log_safe_thread_create(thread_4_exec, (void*)&count_4, "", 12, 1024);s_log_safe_thread_5_p = s_log_safe_thread_create(thread_5_exec, (void*)&count_5, "", 11, 1024);s_log_safe_thread_6_p = s_log_safe_thread_create(thread_6_exec, (void*)&count_6, "", 11, 1024);s_log_safe_thread_7_p = s_log_safe_thread_create(thread_7_exec, (void*)&count_7, "", 10, 1024);while(test_mark != 0) {sleep(1);}return 0;
}

修改完成后运行make命令编译测试程序。

make

运行 make 命令后,会在 ./buld 路径生成目标测试程序。
在这里插入图片描述

d、 运测试程序

cd ./build/./s_log_safe_test

切换到 ./build 路径后执行测试程序,通过 ls 会在路径下发现新生成了一个 gmon.out 文件。
在这里插入图片描述

e、 分析、收集数据

gprof s_log_safe_test gmon.out > profile.txt

通过该命令,可以在路径下看见导出的分析结果文件 profile.txt。在该文件中,详细的记录了 函数的执行时间、调用关系、执行次数等信息。但是还不是特别方便查看,毕竟看图会更直观。
在这里插入图片描述
profile.txt文件的内容如下:

Flat profile:Each sample counts as 0.01 seconds.no time accumulated%   cumulative   self              self     total           time   seconds   seconds    calls  Ts/call  Ts/call  name    0.00      0.00     0.00     2048     0.00     0.00  s_log_safe_mutex_unlock0.00      0.00     0.00     2048     0.00     0.00  s_ring_buffer_unlock0.00      0.00     0.00     1294     0.00     0.00  s_log_safe_mutex_lock0.00      0.00     0.00     1294     0.00     0.00  s_ring_buffer_lock0.00      0.00     0.00      752     0.00     0.00  s_log_safe_mutex_try_lock0.00      0.00     0.00      752     0.00     0.00  s_log_strrchr0.00      0.00     0.00      751     0.00     0.00  s_ring_buffer_try_lock0.00      0.00     0.00      544     0.00     0.00  s_ring_buffer_could_read_num_get0.00      0.00     0.00      383     0.00     0.00  s_log_safe_out0.00      0.00     0.00      376     0.00     0.00  s_log_out_by_printf0.00      0.00     0.00      376     0.00     0.00  s_log_print0.00      0.00     0.00      376     0.00     0.00  s_log_safe_output0.00      0.00     0.00      376     0.00     0.00  s_ring_buffer_read_elements0.00      0.00     0.00      374     0.00     0.00  s_ring_buffer_write_elements0.00      0.00     0.00       78     0.00     0.00  s_log_safe_output_pool_used_get0.00      0.00     0.00        9     0.00     0.00  get_thread_policy0.00      0.00     0.00        9     0.00     0.00  s_log_safe_thread_create0.00      0.00     0.00        2     0.00     0.00  s_log_safe_mutex_create0.00      0.00     0.00        2     0.00     0.00  s_ring_buffer_lock_create0.00      0.00     0.00        1     0.00     0.00  s_log_safe_constructor0.00      0.00     0.00        1     0.00     0.00  s_log_safe_init0.00      0.00     0.00        1     0.00     0.00  s_log_safe_output_pool_cap_get0.00      0.00     0.00        1     0.00     0.00  s_ring_buffer_constructor0.00      0.00     0.00        1     0.00     0.00  s_ring_buffer_element_pool_constructor_malloc%         the percentage of the total running time of the
time       program used by this function.cumulative a running sum of the number of seconds accountedseconds   for by this function and those listed above it.self      the number of seconds accounted for by this
seconds    function alone.  This is the major sort for thislisting.calls      the number of times this function was invoked, ifthis function is profiled, else blank.self      the average number of milliseconds spent in this
ms/call    function per call, if this function is profiled,else blank.total     the average number of milliseconds spent in this
ms/call    function and its descendents per call, if thisfunction is profiled, else blank.name       the name of the function.  This is the minor sortfor this listing. The index shows the location ofthe function in the gprof listing. If the index isin parenthesis it shows where it would appear inthe gprof listing if it were to be printed.Copyright (C) 2012-2015 Free Software Foundation, Inc.Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.Call graph (explanation follows)granularity: each sample hit covers 2 byte(s) no time propagatedindex % time    self  children    called     name0.00    0.00    2048/2048        s_ring_buffer_unlock [2]
[1]      0.0    0.00    0.00    2048         s_log_safe_mutex_unlock [1]
-----------------------------------------------0.00    0.00       2/2048        s_ring_buffer_constructor [23]0.00    0.00     544/2048        s_ring_buffer_could_read_num_get [8]0.00    0.00     750/2048        s_ring_buffer_write_elements [14]0.00    0.00     752/2048        s_ring_buffer_read_elements [13]
[2]      0.0    0.00    0.00    2048         s_ring_buffer_unlock [2]0.00    0.00    2048/2048        s_log_safe_mutex_unlock [1]
-----------------------------------------------0.00    0.00    1294/1294        s_ring_buffer_lock [4]
[3]      0.0    0.00    0.00    1294         s_log_safe_mutex_lock [3]
-----------------------------------------------0.00    0.00     374/1294        s_ring_buffer_write_elements [14]0.00    0.00     376/1294        s_ring_buffer_read_elements [13]0.00    0.00     544/1294        s_ring_buffer_could_read_num_get [8]
[4]      0.0    0.00    0.00    1294         s_ring_buffer_lock [4]0.00    0.00    1294/1294        s_log_safe_mutex_lock [3]
-----------------------------------------------0.00    0.00     752/752         s_ring_buffer_try_lock [7]
[5]      0.0    0.00    0.00     752         s_log_safe_mutex_try_lock [5]
-----------------------------------------------0.00    0.00     752/752         s_log_safe_output [12]
[6]      0.0    0.00    0.00     752         s_log_strrchr [6]
-----------------------------------------------0.00    0.00     375/751         s_ring_buffer_write_elements [14]0.00    0.00     376/751         s_ring_buffer_read_elements [13]
[7]      0.0    0.00    0.00     751         s_ring_buffer_try_lock [7]0.00    0.00     752/752         s_log_safe_mutex_try_lock [5]
-----------------------------------------------0.00    0.00      78/544         s_log_safe_output_pool_used_get [15]0.00    0.00     466/544         s_log_safe_thread_exec_func [36]
[8]      0.0    0.00    0.00     544         s_ring_buffer_could_read_num_get [8]0.00    0.00     544/1294        s_ring_buffer_lock [4]0.00    0.00     544/2048        s_ring_buffer_unlock [2]
-----------------------------------------------0.00    0.00      11/383         thread_7_exec [50]0.00    0.00      22/383         thread_6_exec [49]0.00    0.00      33/383         thread_5_exec [48]0.00    0.00      43/383         thread_4_exec [47]0.00    0.00      55/383         thread_3_exec [46]0.00    0.00      66/383         thread_2_exec [45]0.00    0.00      76/383         thread_1_exec [44]0.00    0.00      77/383         thread_main_exec [51]
[9]      0.0    0.00    0.00     383         s_log_safe_out [9]0.00    0.00     374/374         s_ring_buffer_write_elements [14]
-----------------------------------------------0.00    0.00     376/376         s_log_print [11]
[10]     0.0    0.00    0.00     376         s_log_out_by_printf [10]
-----------------------------------------------0.00    0.00     376/376         s_log_safe_output [12]
[11]     0.0    0.00    0.00     376         s_log_print [11]0.00    0.00     376/376         s_log_out_by_printf [10]
-----------------------------------------------0.00    0.00     376/376         s_log_safe_thread_exec_func [36]
[12]     0.0    0.00    0.00     376         s_log_safe_output [12]0.00    0.00     752/752         s_log_strrchr [6]0.00    0.00     376/376         s_ring_buffer_read_elements [13]0.00    0.00     376/376         s_log_print [11]
-----------------------------------------------0.00    0.00     376/376         s_log_safe_output [12]
[13]     0.0    0.00    0.00     376         s_ring_buffer_read_elements [13]0.00    0.00     752/2048        s_ring_buffer_unlock [2]0.00    0.00     376/751         s_ring_buffer_try_lock [7]0.00    0.00     376/1294        s_ring_buffer_lock [4]
-----------------------------------------------0.00    0.00     374/374         s_log_safe_out [9]
[14]     0.0    0.00    0.00     374         s_ring_buffer_write_elements [14]0.00    0.00     750/2048        s_ring_buffer_unlock [2]0.00    0.00     375/751         s_ring_buffer_try_lock [7]0.00    0.00     374/1294        s_ring_buffer_lock [4]
-----------------------------------------------0.00    0.00      78/78          thread_main_exec [51]
[15]     0.0    0.00    0.00      78         s_log_safe_output_pool_used_get [15]0.00    0.00      78/544         s_ring_buffer_could_read_num_get [8]
-----------------------------------------------0.00    0.00       9/9           s_log_safe_thread_create [17]
[16]     0.0    0.00    0.00       9         get_thread_policy [16]
-----------------------------------------------0.00    0.00       1/9           s_log_safe_init [21]0.00    0.00       8/9           main [30]
[17]     0.0    0.00    0.00       9         s_log_safe_thread_create [17]0.00    0.00       9/9           get_thread_policy [16]
-----------------------------------------------0.00    0.00       2/2           s_ring_buffer_lock_create [19]
[18]     0.0    0.00    0.00       2         s_log_safe_mutex_create [18]
-----------------------------------------------0.00    0.00       2/2           s_ring_buffer_constructor [23]
[19]     0.0    0.00    0.00       2         s_ring_buffer_lock_create [19]0.00    0.00       2/2           s_log_safe_mutex_create [18]
-----------------------------------------------0.00    0.00       1/1           s_log_safe_init [21]
[20]     0.0    0.00    0.00       1         s_log_safe_constructor [20]0.00    0.00       1/1           s_ring_buffer_constructor [23]
-----------------------------------------------0.00    0.00       1/1           main [30]
[21]     0.0    0.00    0.00       1         s_log_safe_init [21]0.00    0.00       1/1           s_log_safe_constructor [20]0.00    0.00       1/9           s_log_safe_thread_create [17]
-----------------------------------------------0.00    0.00       1/1           thread_main_exec [51]
[22]     0.0    0.00    0.00       1         s_log_safe_output_pool_cap_get [22]
-----------------------------------------------0.00    0.00       1/1           s_log_safe_constructor [20]
[23]     0.0    0.00    0.00       1         s_ring_buffer_constructor [23]0.00    0.00       2/2           s_ring_buffer_lock_create [19]0.00    0.00       2/2048        s_ring_buffer_unlock [2]0.00    0.00       1/1           s_ring_buffer_element_pool_constructor_malloc [24]
-----------------------------------------------0.00    0.00       1/1           s_ring_buffer_constructor [23]
[24]     0.0    0.00    0.00       1         s_ring_buffer_element_pool_constructor_malloc [24]
-----------------------------------------------This table describes the call tree of the program, and was sorted bythe total amount of time spent in each function and its children.Each entry in this table consists of several lines.  The line with theindex number at the left hand margin lists the current function.The lines above it list the functions that called this function,and the lines below it list the functions this one called.This line lists:index	A unique number given to each element of the table.Index numbers are sorted numerically.The index number is printed next to every function name soit is easier to look up where the function is in the table.% time	This is the percentage of the `total' time that was spentin this function and its children.  Note that due todifferent viewpoints, functions excluded by options, etc,these numbers will NOT add up to 100%.self	This is the total amount of time spent in this function.children	This is the total amount of time propagated into thisfunction by its children.called	This is the number of times the function was called.If the function called itself recursively, the numberonly includes non-recursive calls, and is followed bya `+' and the number of recursive calls.name	The name of the current function.  The index number isprinted after it.  If the function is a member of acycle, the cycle number is printed between thefunction's name and the index number.For the function's parents, the fields have the following meanings:self	This is the amount of time that was propagated directlyfrom the function into this parent.children	This is the amount of time that was propagated fromthe function's children into this parent.called	This is the number of times this parent called thefunction `/' the total number of times the functionwas called.  Recursive calls to the function are notincluded in the number after the `/'.name	This is the name of the parent.  The parent's indexnumber is printed after it.  If the parent is amember of a cycle, the cycle number is printed betweenthe name and the index number.If the parents of the function cannot be determined, the word`<spontaneous>' is printed in the `name' field, and all the otherfields are blank.For the function's children, the fields have the following meanings:self	This is the amount of time that was propagated directlyfrom the child into the function.children	This is the amount of time that was propagated from thechild's children to the function.called	This is the number of times the function calledthis child `/' the total number of times the childwas called.  Recursive calls by the child are notlisted in the number after the `/'.name	This is the name of the child.  The child's indexnumber is printed after it.  If the child is amember of a cycle, the cycle number is printedbetween the name and the index number.If there are any cycles (circles) in the call graph, there is anentry for the cycle-as-a-whole.  This entry shows who called thecycle (as parents) and the members of the cycle (as children.)The `+' recursive calls entry shows the number of function calls thatwere internal to the cycle, and the calls entry for each member shows,for that member, how many times it was called from other members ofthe cycle.Copyright (C) 2012-2015 Free Software Foundation, Inc.Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved.Index by function name[16] get_thread_policy (s_log_safe_platform.c) [1] s_log_safe_mutex_unlock [8] s_ring_buffer_could_read_num_get[10] s_log_out_by_printf     [9] s_log_safe_out         [24] s_ring_buffer_element_pool_constructor_malloc[11] s_log_print            [12] s_log_safe_output (s_log_safe.c) [4] s_ring_buffer_lock[20] s_log_safe_constructor (s_log_safe.c) [22] s_log_safe_output_pool_cap_get [19] s_ring_buffer_lock_create[21] s_log_safe_init        [15] s_log_safe_output_pool_used_get [13] s_ring_buffer_read_elements[18] s_log_safe_mutex_create [17] s_log_safe_thread_create [7] s_ring_buffer_try_lock[3] s_log_safe_mutex_lock   [6] s_log_strrchr           [2] s_ring_buffer_unlock[5] s_log_safe_mutex_try_lock [23] s_ring_buffer_constructor [14] s_ring_buffer_write_elements

f、 生成调用图

gprof2dot -e0 -n0 profile.txt > profile.dot
dot profile.dot -Tpng -o profile.png

通过 gprof2dot 和 dot 工具能够将 profile.txt 文件转换为 更直观的 图片。
在这里插入图片描述
在这里插入图片描述

如果没有安装 gprof2dot 和 dot 工具,可以通过以下命令进行安装:

sudo apt-get install graphvizpip3 install gprof2dot

g、 查看调用图

通过上述操作,最终生成了 profile.png 文件,最终的调用图如下图所示:
在这里插入图片描述
从该图中,就比较直观的看到了调用流程和调用次数


4 小结

上述的通过 gprof 和相关工具 对目标程序 进行 性能分析,是日常开发过程中常用的一种方式。

这篇关于如何使用gprof对程序进行性能分析的文章就介绍到这儿,希望我们推荐的文章对编程师们有所帮助!



http://www.chinasem.cn/article/1085645

相关文章

使用Python实现可恢复式多线程下载器

《使用Python实现可恢复式多线程下载器》在数字时代,大文件下载已成为日常操作,本文将手把手教你用Python打造专业级下载器,实现断点续传,多线程加速,速度限制等功能,感兴趣的小伙伴可以了解下... 目录一、智能续传:从崩溃边缘抢救进度二、多线程加速:榨干网络带宽三、速度控制:做网络的好邻居四、终端交互

Python中注释使用方法举例详解

《Python中注释使用方法举例详解》在Python编程语言中注释是必不可少的一部分,它有助于提高代码的可读性和维护性,:本文主要介绍Python中注释使用方法的相关资料,需要的朋友可以参考下... 目录一、前言二、什么是注释?示例:三、单行注释语法:以 China编程# 开头,后面的内容为注释内容示例:示例:四

Go语言数据库编程GORM 的基本使用详解

《Go语言数据库编程GORM的基本使用详解》GORM是Go语言流行的ORM框架,封装database/sql,支持自动迁移、关联、事务等,提供CRUD、条件查询、钩子函数、日志等功能,简化数据库操作... 目录一、安装与初始化1. 安装 GORM 及数据库驱动2. 建立数据库连接二、定义模型结构体三、自动迁

ModelMapper基本使用和常见场景示例详解

《ModelMapper基本使用和常见场景示例详解》ModelMapper是Java对象映射库,支持自动映射、自定义规则、集合转换及高级配置(如匹配策略、转换器),可集成SpringBoot,减少样板... 目录1. 添加依赖2. 基本用法示例:简单对象映射3. 自定义映射规则4. 集合映射5. 高级配置匹

MySQL中的表连接原理分析

《MySQL中的表连接原理分析》:本文主要介绍MySQL中的表连接原理分析,具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教... 目录1、背景2、环境3、表连接原理【1】驱动表和被驱动表【2】内连接【3】外连接【4编程】嵌套循环连接【5】join buffer4、总结1、背景

Spring 框架之Springfox使用详解

《Spring框架之Springfox使用详解》Springfox是Spring框架的API文档工具,集成Swagger规范,自动生成文档并支持多语言/版本,模块化设计便于扩展,但存在版本兼容性、性... 目录核心功能工作原理模块化设计使用示例注意事项优缺点优点缺点总结适用场景建议总结Springfox 是

嵌入式数据库SQLite 3配置使用讲解

《嵌入式数据库SQLite3配置使用讲解》本文强调嵌入式项目中SQLite3数据库的重要性,因其零配置、轻量级、跨平台及事务处理特性,可保障数据溯源与责任明确,详细讲解安装配置、基础语法及SQLit... 目录0、惨痛教训1、SQLite3环境配置(1)、下载安装SQLite库(2)、解压下载的文件(3)、

Golang如何对cron进行二次封装实现指定时间执行定时任务

《Golang如何对cron进行二次封装实现指定时间执行定时任务》:本文主要介绍Golang如何对cron进行二次封装实现指定时间执行定时任务问题,具有很好的参考价值,希望对大家有所帮助,如有错误... 目录背景cron库下载代码示例【1】结构体定义【2】定时任务开启【3】使用示例【4】控制台输出总结背景

使用Python绘制3D堆叠条形图全解析

《使用Python绘制3D堆叠条形图全解析》在数据可视化的工具箱里,3D图表总能带来眼前一亮的效果,本文就来和大家聊聊如何使用Python实现绘制3D堆叠条形图,感兴趣的小伙伴可以了解下... 目录为什么选择 3D 堆叠条形图代码实现:从数据到 3D 世界的搭建核心代码逐行解析细节优化应用场景:3D 堆叠图

Springboot如何正确使用AOP问题

《Springboot如何正确使用AOP问题》:本文主要介绍Springboot如何正确使用AOP问题,具有很好的参考价值,希望对大家有所帮助,如有错误或未考虑完全的地方,望不吝赐教... 目录​一、AOP概念二、切点表达式​execution表达式案例三、AOP通知四、springboot中使用AOP导出