查看 OceanBase 执行计划
使用benchmarksql压测数据库,产生高消耗的sql并测试数据库性能
压测环境部署
benchmarksql下载
git clone https://github.com/meiq4096/benchmarksql-5.0.git
修改配置文件
vi ./run/props.ob
db=oracle
driver=com.alipay.oceanbase.obproxy.mysql.jdbc.Driver
conn=jdbc:oceanbase://192.168.56.20:2883/tpcc?useUnicode=true&characterEncoding=utf-8
user=datax@mq_t1
password=datax
warehouses=2
loadWorkers=2
terminals=5
//To run specified transactions per terminal- runMins must equal zero
runTxnsPerTerminal=0
//To run for specified minutes- runTxnsPerTerminal must equal zero
runMins=3
//Number of total transactions per minute
limitTxnsPerMin=0
//Set to true to run in 4.x compatible mode. Set to false to use the
//entire configured database evenly.
terminalWarehouseFixed=true
//The following five values must add up to 100
newOrderWeight=45
paymentWeight=43
orderStatusWeight=4
deliveryWeight=4
stockLevelWeight=4
// Directory name to create for collecting detailed result data.
// Comment this out to suppress.
resultDirectory=my_result_%tY-%tm-%td_%tH%tM%tS
osCollectorScript=./misc/os_collector_linux.py
osCollectorInterval=1
数据准备
建表
[root@innodb-cluster01 run]# sh runSQL.sh props.ob sql.common/tableCreates.sql
runSQL.sh: line 14: source: funcs.sh: file not found
--问题
runSQL.sh 提示行数的funcs.sh改为绝对路径
调整数据库参数
set global autocommit=ON;
set global ob_query_timeout=36000000000;
set global ob_trx_timeout=36000000000;
set global max_allowed_packet=67108864;
set global ob_sql_work_area_percentage=100;
set global parallel_servers_target=800;
装载数据
[root@innodb-cluster01 run]# sh runLoader.sh props.ob
runLoader.sh: line 8: source: funcs.sh: file not found
--问题
runLoader.sh 提示行数的funcs.sh改为绝对路径
Starting BenchmarkSQL LoadData
driver=com.alipay.oceanbase.obproxy.mysql.jdbc.Driver
conn=jdbc:oceanbase://192.168.56.20:2883/tpcc?useUnicode=true&characterEncoding=utf-8
user=datax@mq_t1
password=***********
warehouses=2
loadWorkers=2
fileLocation (not defined)
csvNullValue (not defined - using default 'NULL')
Worker 000: Loading ITEM
Worker 001: Loading Warehouse 1
Worker 000: Loading ITEM done
Worker 000: Loading Warehouse 2
Worker 001: Loading Warehouse 1 done
Worker 000: Loading Warehouse 2 done
创建索引
cat sql.common/indexCreates.sql
alter table bmsql_warehouse add constraint bmsql_warehouse_pkey
primary key (w_id);
alter table bmsql_district add constraint bmsql_district_pkey
primary key (d_w_id, d_id);
alter table bmsql_customer add constraint bmsql_customer_pkey
primary key (c_w_id, c_d_id, c_id);
create index bmsql_customer_idx1
on bmsql_customer (c_w_id, c_d_id, c_last, c_first);
alter table bmsql_oorder add constraint bmsql_oorder_pkey
primary key (o_w_id, o_d_id, o_id);
create unique index bmsql_oorder_idx1
on bmsql_oorder (o_w_id, o_d_id, o_carrier_id, o_id);
alter table bmsql_new_order add constraint bmsql_new_order_pkey
primary key (no_w_id, no_d_id, no_o_id);
alter table bmsql_order_line add constraint bmsql_order_line_pkey
primary key (ol_w_id, ol_d_id, ol_o_id, ol_number);
alter table bmsql_stock add constraint bmsql_stock_pkey
primary key (s_w_id, s_i_id);
alter table bmsql_item add constraint bmsql_item_pkey
primary key (i_id);
性能测试
[root@innodb-cluster01 run]#sh runBenchmark.sh props.ob
10:46:22,654 [main] INFO jTPCC : Term-00,
10:46:22,658 [main] INFO jTPCC : Term-00, +-------------------------------------------------------------+
10:46:22,658 [main] INFO jTPCC : Term-00, BenchmarkSQL v5.0
10:46:22,658 [main] INFO jTPCC : Term-00, +-------------------------------------------------------------+
10:46:22,658 [main] INFO jTPCC : Term-00, (c) 2003, Raul Barbosa
10:46:22,658 [main] INFO jTPCC : Term-00, (c) 2004-2016, Denis Lussier
10:46:22,661 [main] INFO jTPCC : Term-00, (c) 2016, Jan Wieck
10:46:22,661 [main] INFO jTPCC : Term-00, +-------------------------------------------------------------+
10:46:22,661 [main] INFO jTPCC : Term-00,
10:46:22,661 [main] INFO jTPCC : Term-00, db=oracle
10:46:22,661 [main] INFO jTPCC : Term-00, driver=com.alipay.oceanbase.obproxy.mysql.jdbc.Driver
10:46:22,661 [main] INFO jTPCC : Term-00, conn=jdbc:oceanbase://192.168.56.20:2883/tpcc?useUnicode=true&characterEncoding=utf-8
10:46:22,661 [main] INFO jTPCC : Term-00, user=datax@mq_t1
10:46:22,662 [main] INFO jTPCC : Term-00,
10:46:22,662 [main] INFO jTPCC : Term-00, warehouses=2
10:46:22,662 [main] INFO jTPCC : Term-00, terminals=5
10:46:22,665 [main] INFO jTPCC : Term-00, runMins=3
10:46:22,665 [main] INFO jTPCC : Term-00, limitTxnsPerMin=0
10:46:22,665 [main] INFO jTPCC : Term-00, terminalWarehouseFixed=true
10:46:22,665 [main] INFO jTPCC : Term-00,
10:46:22,665 [main] INFO jTPCC : Term-00, newOrderWeight=45
10:46:22,665 [main] INFO jTPCC : Term-00, paymentWeight=43
10:46:22,666 [main] INFO jTPCC : Term-00, orderStatusWeight=4
10:46:22,666 [main] INFO jTPCC : Term-00, deliveryWeight=4
10:46:22,666 [main] INFO jTPCC : Term-00, stockLevelWeight=4
10:46:22,666 [main] INFO jTPCC : Term-00,
10:46:22,666 [main] INFO jTPCC : Term-00, resultDirectory=my_result_%tY-%tm-%td_%tH%tM%tS
10:46:22,666 [main] INFO jTPCC : Term-00, osCollectorScript=./misc/os_collector_linux.py
10:46:22,666 [main] INFO jTPCC : Term-00,
10:46:22,679 [main] INFO jTPCC : Term-00, copied props.ob to my_result_2024-03-10_104622/run.properties
10:46:22,679 [main] INFO jTPCC : Term-00, created my_result_2024-03-10_104622/data/runInfo.csv for runID 7
10:46:22,680 [main] INFO jTPCC : Term-00, writing per transaction results to my_result_2024-03-10_104622/data/result.csv
10:46:22,681 [main] INFO jTPCC : Term-00, osCollectorScript=./misc/os_collector_linux.py
10:46:22,681 [main] INFO jTPCC : Term-00, osCollectorInterval=1
10:46:22,681 [main] INFO jTPCC : Term-00, osCollectorSSHAddr=null
10:46:22,681 [main] INFO jTPCC : Term-00, osCollectorDevices=null
10:46:22,754 [main] INFO jTPCC : Term-00,
10:46:23,088 [main] INFO jTPCC : Term-00, C value for C_LAST during load: 174
10:46:23,088 [main] INFO jTPCC : Term-00, C value for C_LAST this run: 246
10:46:23,088 [main] INFO jTPCC : Term-00,
Term-00, Running Average tpmTOTAL: 880.90 Current tpmTOTAL: 888 Memory Usage: 48MB / 236MB
Term-00, Running Average tpmTOTAL: 1330.69 Current tpmTOTAL: 12456 Memory Usage: 36MB / 228MB
Term-00, Running Average tpmTOTAL: 1069.82 Current tpmTOTAL: 20892 Memory Usage: 7MB / 219MB
Term-00, Running Average tpmTOTAL: 830.32 Current tpmTOTAL: 20472 Memory Usage: 9MB / 219MB
10:50:10,596 [Thread-5] INFO jTPCC : Term-00,
10:50:10,597 [Thread-5] INFO jTPCC : Term-00,
10:50:10,597 [Thread-5] INFO jTPCC : Term-00, Measured tpmC (NewOrders) = 380.2
10:50:10,597 [Thread-5] INFO jTPCC : Term-00, Measured tpmTOTAL = 830.32
10:50:10,597 [Thread-5] INFO jTPCC : Term-00, Session Start = 2024-03-10 10:46:23
10:50:10,597 [Thread-5] INFO jTPCC : Term-00, Session End = 2024-03-10 10:50:10
10:50:10,597 [Thread-5] INFO jTPCC : Term-00, Transaction Count = 3146
tpmC用来衡量IOPS.
Transaction用来衡量TPS.
分析top sql
查询top sql
SELECT sql_id, count(*), round(avg(elapsed_time)) avg_elapsed_time,
round(avg(execute_time)) avg_exec_time
FROM GV$OB_SQL_AUDIT s
WHERE DB_NAME='tpcc'
GROUP BY sql_id
order by avg_elapsed_time desc limit 10;
+----------------------------------+----------+------------------+---------------+
| sql_id | count(*) | avg_elapsed_time | avg_exec_time |
+----------------------------------+----------+------------------+---------------+
| B447DE16B3F42D2409B2A2BE50328E63 | 1 | 76518226 | 247658 |
| F59A700FA168324279B0DBC25E19760F | 1 | 76359957 | 64612631 |
| AB92F1B97A8D4DADFD477BB52C65A00B | 2 | 38008119 | 5118976 |
| AE32C84F890055A535A28B262C649D41 | 3 | 25339948 | 3428539 |
| F0EFFFCD85E71C241661E66EEA047C58 | 10 | 7604399 | 1026657 |
| 482BA7822AE7BE644CEBEB55213E7284 | 9 | 3071 | 3007 |
| AD9112FD1D4FF113292E5FE777B22F3C | 9 | 1693 | 1420 |
| 8D6E84735C0B8FB1823D199E2CA141C8 | 9 | 1586 | 1424 |
| EC66B09D06D688727D0F999BFCFF5348 | 9 | 816 | 115 |
| F95CD7A05C7064A028D76E0088B147F7 | 9 | 561 | 199 |
+----------------------------------+----------+------------------+---------------+
查询对应的前三个sql
obclient [oceanbase]> select sql_id,QUERY_SQL from GV$OB_SQL_AUDIT where sql_id in('B447DE16B3F42D2409B2A2BE50328E63','F59A700FA168324279B0DBC25E19760F','AB92F1B97A8D4DADFD477BB52C65A00B')\G
*************************** 1. row ***************************
sql_id: AB92F1B97A8D4DADFD477BB52C65A00B
QUERY_SQL: SELECT c_id FROM bmsql_customer WHERE c_w_id = 2 AND c_d_id = 9 AND c_last = 'ATIONOUGHTPRI' ORDER BY c_first
*************************** 2. row ***************************
sql_id: F59A700FA168324279B0DBC25E19760F
QUERY_SQL: SELECT count(*) AS low_stock FROM ( SELECT s_w_id, s_i_id, s_quantity FROM bmsql_stock WHERE s_w_id = 1 AND s_quantity < 12 AND s_i_id IN ( SELECT ol_i_id FROM bmsql_district JOIN bmsql_order_line ON ol_w_id = d_w_id AND ol_d_id = d_id AND ol_o_id >= d_next_o_id - 20 AND ol_o_id < d_next_o_id WHERE d_w_id = 1 AND d_id = 9 ) )
*************************** 3. row ***************************
sql_id: B447DE16B3F42D2409B2A2BE50328E63
QUERY_SQL: UPDATE bmsql_warehouse SET w_ytd = w_ytd + 4691.27 WHERE w_id = 2
*************************** 4. row ***************************
sql_id: AB92F1B97A8D4DADFD477BB52C65A00B
QUERY_SQL: SELECT c_id FROM bmsql_customer WHERE c_w_id = 1 AND c_d_id = 1 AND c_last = 'PRESPRESANTI' ORDER BY c_first
4 rows in set (0.009 sec)
使用explain查看sql的执行计划
obclient [oceanbase]> select sql_id,QUERY_SQL from GV$OB_SQL_AUDIT where sql_id in('B447DE16B3F42D2409B2A2BE50328E63','F59A700FA168324279B0DBC25E19760F','AB92F1B97A8D4DADFD477BB52C65A00B')\G
*************************** 1. row ***************************
sql_id: AB92F1B97A8D4DADFD477BB52C65A00B
QUERY_SQL: SELECT c_id FROM bmsql_customer WHERE c_w_id = 2 AND c_d_id = 9 AND c_last = 'ATIONOUGHTPRI' ORDER BY c_first
*************************** 2. row ***************************
sql_id: F59A700FA168324279B0DBC25E19760F
QUERY_SQL: SELECT count(*) AS low_stock FROM ( SELECT s_w_id, s_i_id, s_quantity FROM bmsql_stock WHERE s_w_id = 1 AND s_quantity < 12 AND s_i_id IN ( SELECT ol_i_id FROM bmsql_district JOIN bmsql_order_line ON ol_w_id = d_w_id AND ol_d_id = d_id AND ol_o_id >= d_next_o_id - 20 AND ol_o_id < d_next_o_id WHERE d_w_id = 1 AND d_id = 9 ) )
*************************** 3. row ***************************
sql_id: B447DE16B3F42D2409B2A2BE50328E63
QUERY_SQL: UPDATE bmsql_warehouse SET w_ytd = w_ytd + 4691.27 WHERE w_id = 2
*************************** 4. row ***************************
sql_id: AB92F1B97A8D4DADFD477BB52C65A00B
QUERY_SQL: SELECT c_id FROM bmsql_customer WHERE c_w_id = 1 AND c_d_id = 1 AND c_last = 'PRESPRESANTI' ORDER BY c_first
4 rows in set (0.009 sec)
obclient [tpcc]> explain SELECT c_id FROM bmsql_customer WHERE c_w_id = 2 AND c_d_id = 9 AND c_last = 'ATIONOUGHTPRI' ORDER BY c_first;
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| =============================================================================== |
| |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| |
| ------------------------------------------------------------------------------- |
| |0 |TABLE RANGE SCAN|bmsql_customer(bmsql_customer_idx1)|12 |5 | |
| =============================================================================== |
| Outputs & filters: |
| ------------------------------------- |
| 0 - output([bmsql_customer.c_id]), filter(nil), rowset=16 |
| access([bmsql_customer.c_id]), partitions(p0) |
| is_index_back=false, is_global_index=false, |
| range_key([bmsql_customer.c_w_id], [bmsql_customer.c_d_id], [bmsql_customer.c_last], [bmsql_customer.c_first], [bmsql_customer.c_id]), range(2,9,ATIONOUGHTPRI, |
| MIN,MIN ; 2,9,ATIONOUGHTPRI,MAX,MAX), |
| range_cond([bmsql_customer.c_w_id = 2], [bmsql_customer.c_d_id = 9], [bmsql_customer.c_last = 'ATIONOUGHTPRI']) |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
13 rows in set (0.006 sec)
obclient [tpcc]> explain SELECT count(*) AS low_stock FROM ( SELECT s_w_id, s_i_id, s_quantity FROM bmsql_stock WHERE s_w_id = 1 AND s_quantity < 12 AND s_i_id IN ( SELECT ol_i_id FROM bmsql_district JOIN bmsql_order_line ON ol_w_id = d_w_id AND ol_d_id = d_id AND ol_o_id >= d_next_o_id - 20 AND ol_o_id < d_next_o_id WHERE d_w_id = 1 AND d_id = 9 ) )
->
-> ;
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| ====================================================================== |
| |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| |
| ---------------------------------------------------------------------- |
| |0 |SCALAR GROUP BY | |1 |42 | |
| |1 |└─NESTED-LOOP JOIN | |2 |42 | |
| |2 | ├─SUBPLAN SCAN |VIEW2 |2 |11 | |
| |3 | │ └─HASH DISTINCT | |2 |11 | |
| |4 | │ └─NESTED-LOOP JOIN | |2 |11 | |
| |5 | │ ├─TABLE RANGE SCAN|bmsql_order_line|30 |7 | |
| |6 | │ └─MATERIAL | |1 |3 | |
| |7 | │ └─TABLE GET |bmsql_district |1 |3 | |
| |8 | └─DISTRIBUTED TABLE GET |bmsql_stock |1 |21 | |
| ====================================================================== |
| Outputs & filters: |
| ------------------------------------- |
| 0 - output([T_FUN_COUNT(*)]), filter(nil), rowset=256 |
| group(nil), agg_func([T_FUN_COUNT(*)]) |
| 1 - output(nil), filter(nil), rowset=256 |
| conds(nil), nl_params_([VIEW2.VIEW1.ol_i_id(:3)]), use_batch=false |
| 2 - output([VIEW2.VIEW1.ol_i_id]), filter(nil), rowset=256 |
| access([VIEW2.VIEW1.ol_i_id]) |
| 3 - output([bmsql_order_line.ol_i_id]), filter(nil), rowset=256 |
| distinct([bmsql_order_line.ol_i_id]) |
| 4 - output([bmsql_order_line.ol_i_id]), filter(nil), rowset=256 |
| conds([bmsql_order_line.ol_o_id < bmsql_district.d_next_o_id], [bmsql_order_line.ol_o_id >= bmsql_district.d_next_o_id - 20]), nl_params_(nil), use_batch=false |
| 5 - output([bmsql_order_line.ol_o_id], [bmsql_order_line.ol_i_id]), filter(nil), rowset=256 |
| access([bmsql_order_line.ol_o_id], [bmsql_order_line.ol_i_id]), partitions(p0) |
| is_index_back=false, is_global_index=false, |
| range_key([bmsql_order_line.ol_w_id], [bmsql_order_line.ol_d_id], [bmsql_order_line.ol_o_id], [bmsql_order_line.ol_number]), range(1,9,MIN,MIN ; 1, |
| 9,MAX,MAX), |
| range_cond([bmsql_order_line.ol_w_id = 1], [bmsql_order_line.ol_d_id = 9]) |
| 6 - output([bmsql_district.d_next_o_id], [bmsql_district.d_next_o_id - 20]), filter(nil), rowset=256 |
| 7 - output([bmsql_district.d_next_o_id], [bmsql_district.d_next_o_id - 20]), filter([bmsql_district.d_next_o_id > bmsql_district.d_next_o_id - 20]), rowset=256 |
| access([bmsql_district.d_next_o_id]), partitions(p0) |
| is_index_back=false, is_global_index=false, filter_before_indexback[false], |
| range_key([bmsql_district.d_w_id], [bmsql_district.d_id]), range[1,9 ; 1,9], |
| range_cond([bmsql_district.d_w_id = 1], [bmsql_district.d_id = 9]) |
| 8 - output(nil), filter([bmsql_stock.s_quantity < 12]), rowset=256 |
| access([bmsql_stock.s_quantity]), partitions(p0) |
| is_index_back=false, is_global_index=false, filter_before_indexback[false], |
| range_key([bmsql_stock.s_w_id], [bmsql_stock.s_i_id]), range(MIN ; MAX), |
| range_cond([bmsql_stock.s_w_id = 1], [bmsql_stock.s_i_id = :3]) |
+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
42 rows in set (0.061 sec)
obclient [tpcc]> explain SELECT c_id FROM bmsql_customer WHERE c_w_id = 1 AND c_d_id = 1 AND c_last = 'PRESPRESANTI' ORDER BY c_first;
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| Query Plan |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| =============================================================================== |
| |ID|OPERATOR |NAME |EST.ROWS|EST.TIME(us)| |
| ------------------------------------------------------------------------------- |
| |0 |TABLE RANGE SCAN|bmsql_customer(bmsql_customer_idx1)|1 |4 | |
| =============================================================================== |
| Outputs & filters: |
| ------------------------------------- |
| 0 - output([bmsql_customer.c_id]), filter(nil), rowset=16 |
| access([bmsql_customer.c_id]), partitions(p0) |
| is_index_back=false, is_global_index=false, |
| range_key([bmsql_customer.c_w_id], [bmsql_customer.c_d_id], [bmsql_customer.c_last], [bmsql_customer.c_first], [bmsql_customer.c_id]), range(1,1,PRESPRESANTI, |
| MIN,MIN ; 1,1,PRESPRESANTI,MAX,MAX), |
| range_cond([bmsql_customer.c_w_id = 1], [bmsql_customer.c_d_id = 1], [bmsql_customer.c_last = 'PRESPRESANTI']) |
+----------------------------------------------------------------------------------------------------------------------------------------------------------------------+
13 rows in set (0.007 sec)
查看 OceanBase 执行计划的更多相关文章
- 如何查看MySQL执行计划
在介绍怎么查看MySQL执行计划前,我们先来看个后面会提到的名词解释: 覆盖索引: MySQL可以利用索引返回select列表中的字段,而不必根据索引再次读取数据文件 包含所有满足查询需要的数据的索引 ...
- 查看SQL执行计划
一用户进入某界面慢得要死,查看SQL执行计划如下(具体SQL语句就不完全公布了,截断的如下): call count cpu elapsed disk ...
- 查看Oracle执行计划的几种方法
查看Oracle执行计划的几种方法 一.通过PL/SQL Dev工具 1.直接File->New->Explain Plan Window,在窗口中执行sql可以查看计划结果.其中,Cos ...
- 查看Mysql执行计划
使用navicat查看mysql执行计划: 打开profile分析工具: 查看是否生效:show variable like ‘%profil%’; 查看进程:show processlist; 选择 ...
- Oracle查看SQL执行计划的方式
Oracle查看SQL执行计划的方式 获取Oracle sql执行计划并查看执行计划,是掌握和判断数据库性能的基本技巧.下面案例介绍了多种查看sql执行计划的方式: 基本有以下几种方式: ...
- EXPLAIN 查看 SQL 执行计划
EXPLAIN 查看 SQL 执行计划.分析索引的效率: id:id 列数字越大越先执行: 如果说数字一样大,那么就从上往下依次执行,id列为null的就表是这是一个结果集,不需要使用它来进行查询. ...
- 查看Oracle执行计划
1.PL/SQL解释计划窗口 优点:方面 缺点:看到信息有限 2.explain_plan for 针对某个句子优化较方便 3.sqlplus Sqlplus里输入命令: set autotrace ...
- 查看ORACLE执行计划的几种常用方法
SQL的执行计划实际代表了目标SQL在Oracle数据库内部的具体执行步骤,作为调优,只有知道了优化器选择的执行计划是否为当前情形下最优的执行计划,才能够知道下一步往什么方向. 执行计划的定义:执行目 ...
- MySQL EXPLAIN 命令: 查看查询执行计划
MySQL 的 EXPLAIN 命令可以查看SELECT语句的执行的计划,是 MySQL 查询优化的必备工具. 通过执行计划可以了解查询方式.索引使用情况.需要扫描的数据量以及是否需要临时表或排序操作 ...
- plsql中查看sql执行计划
想要优化sql语句,可以从sql执行计划入手. 在plsql客户端,提供了一个方便的按钮来查看执行计划 选中需要查看的sql语句,点击此按钮,就可以看到该条语句的执行计划了. 结果集包括描述,用户,对 ...
随机推荐
- Elasticsearch之常见问题
一. 聚合操作时,报Fielddata is disabled on text fields by default GET /megacorp/employee/_search { "agg ...
- pve 下的群晖虚拟机硬盘空间扩容的记录
pve下,105号群晖虚拟机,btrfs系统,sata硬盘. 虚拟机容量硬盘130G,扩展至140G,还需要命令行和网页存储管理器界面操作,以实现扩容的目的. df -h Filesystem Siz ...
- Python 爬虫必备杀器，xpath 解析 HTML
最近工作上写了个爬虫,要爬取国家标准网上的一些信息,这自然离不了 Python,而在解析 HTML 方面,xpath 则可当仁不让的成为兵器谱第一. 你可能之前听说或用过其它的解析方式,像 Beaut ...
- 超详细 HarmonyOS 开发教程之开发环境搭建指南
HarmonyOS开发环境搭建指南:DevEco Studio安装教程 一.系统要求 操作系统:Windows 10 64位或更高版本 RAM:至少8GB,推荐16GB 硬盘空间:至少10GB可用空间 ...
- ZCMU-1153
思路 一个感觉是规律问题的数学问题 因为输入的是n所以要的出有关n的关系或者关系 有关排序,所以可以从位次入手,设双胞胎前一个位置在ai,后一个在bi. Sum(bi-ai)=(2+3+4+5+6+. ...
- Playfair密码
Playfair密码 Playfair cipher (普莱费尔密码)一种古典对称式密码,是首个双字母替换的加密法.尽管以现在的眼光来看这种加密是非常不安全的,但是它加密的过程还是蛮有意思的. 这种加 ...
- N皇后问题（DFS-深度优先算法）
N皇后问题(DFS-深度优先算法) 题目描述: 在 N×N 的方格棋盘放置了 N 个皇后,使得它们不相互攻击(即任意 22 个皇后不允许处在同一排,同一列,也不允许处在与棋盘边框成 45° 的斜线上. ...
- 在Windows下为CodeBlocks20.3安装、配置wxWidget3.2.6
0.前言 CodeBlocks是使用C++编写程序的一个很好的开发环境,最大的好处是它是开源的.免费的,而不仅仅是因为它具有跨平台的能力.还有一个很重要的原因是在CodeBlocks中可以使用wxWi ...
- Http请求报文(请求行，请求头、请求体)
Http请求报文: http请求报文由3部分组成,请求行,请求头,请求体. 一.请求行: 请求方法.URL地址.协议版本 请求方法:POST.GET.DELETE.PUT.HEAD.OPTIONS.T ...
- 中电金信：ChatGPT一夜爆火，知识图谱何以应战？
随着ChatGPT的爆火出圈 人工智能再次迎来发展小高潮 那么作为此前搜索领域的主流技术 知识图谱前路又将如何呢? 事实上,ChatGPT也 ...