[20180123]测试SQLNET.EXPIRE_TIME参数.txt
[20180123]测试SQLNET.EXPIRE_TIME参数.txt
--//曾经写过一篇linux内核网络参数测试tcp_keepalive,链接http://blog.itpub.net/267265/viewspace-2138391/
--//测试服务端会定时发起连接监测与client的连接状态.
参数解析:
/proc/sys/net/ipv4/tcp_keepalive_time 当keepalive起用的时候，TCP发送keepalive消息的频度。默认是2小时。
/proc/sys/net/ipv4/tcp_keepalive_intvl 当探测没有确认时，keepalive探测包的发送间隔。缺省是75秒。
/proc/sys/net/ipv4/tcp_keepalive_probes 如果对方不予应答，keepalive探测包的发送次数。缺省值是9。
--//我发现我遗漏的一种情况的测试,使用SQLNET.EXPIRE_TIME参数,这个参数与前面的内核参数意思差不多.定时监测服务端与客户端连
--//接情况.但是注意这种测试是有服务端发起,一些状态防火墙不允许这样的包通过,我们的分院与总院正好有这样的环境,不知道是否网管
--//配置错误,正好利用这个环境测试看看.主要目的测试设置SQLNET.EXPIRE_TIME情况下,如果无法连上client,是否探测多次,间隔时间是多少.
--//知道这些数值对于理解我遇到的一个问题帮助很大,另发文写一篇blog.
1.环境:
--//服务端IP:192.168.100.106
--//客户端IP:192.168.90.14
--//服务端:
# echo /proc/sys/net/ipv4/tcp_keepalive* | xargs -n 1 strings -1 -f
/proc/sys/net/ipv4/tcp_keepalive_intvl: 75
/proc/sys/net/ipv4/tcp_keepalive_probes: 9
/proc/sys/net/ipv4/tcp_keepalive_time: 7200
--//客户端
# echo /proc/sys/net/ipv4/tcp_keepalive* | xargs -n 1 strings -1 -f
/proc/sys/net/ipv4/tcp_keepalive_intvl: 10
/proc/sys/net/ipv4/tcp_keepalive_probes: 4
/proc/sys/net/ipv4/tcp_keepalive_time: 200
--//在sqlnet.ora文件中配置
sqlnet.expire_time = 10
--//注:rac环境实际上还是读取oracle用户的$ORACLE_HOME/network/admin/sqlnet.ora.而不是grid用户下的$ORACLE_HOME/network/admin/sqlnet.ora.
--//浪费N多时间.^_^.这样后面的错误的间隔就很好解析了.原来看到的sqlnet.expire_time = 5不对.
2.测试:
--//客户端使用sqlplus连接数据库:
xxxxx>
SELECT s.sid, s.serial#, s.process, s.server, p.spid, p.pid, p.serial# p_serial#,'alter system kill session
'''||s.sid||','||s.serial#||''''||' immediate;' c50
FROM v$session s, v$process p
WHERE s.sid in (
SELECT sid
FROM v$mystat
WHERE rownum = 1)
AND s.paddr = p.addr;
SID SERIAL# PROCESS SERVER SPID PID P_SERIAL# C50
---------- ---------- ------------------------ --------- ------ ------- ---------- --------------------------------------------------
6656 50071 22214 DEDICATED 6980 69 200 alter system kill session '6656,50071' immediate;
--//确定服务端进程号=6980
--//服务端:
# lsof -i -P -n | grep "6980 oracle"
oracle 6980 oracle 8u IPv4 3826220323 0t0 UDP 127.0.0.1:58395
oracle 6980 oracle 14u IPv4 3826216194 0t0 UDP 127.0.0.1:58118
oracle 6980 oracle 18u IPv4 3826173598 0t0 TCP 192.168.100.106:1521->192.168.90.14:41203 (ESTABLISHED)
--//确定client的端口号41203.
# tcpdump -i bondeth0 host 192.168.90.15 and port 41203 -nn -vv
tcpdump: listening on bondeth0, link-type EN10MB (Ethernet), capture size 96 bytes
--//客户端执行一些sql语句以后:
xxxxx> select sysdate from dual ;
SYSDATE
-------------------
2018-01-23 11:52:58
--//客户端打开监测:(注意网络接口不要选择错误!!我测试环境是是bond1):
# tcpdump -i bond1 host 192.168.90.14 and port 41203 -nn -vv
tcpdump: listening on bond1, link-type EN10MB (Ethernet), capture size 65535 bytes
...
--//服务端打开监测:
# tcpdump -i bondeth0 host 192.168.90.14 and port 41203 -nn -vv
tcpdump: listening on bondeth0, link-type EN10MB (Ethernet), capture size 96 bytes
11:52:58.146050 IP (tos 0x0, ttl 61, id 37349, offset 0, flags [DF], proto: TCP (6), length: 346) 192.168.90.14.41203 > 192.168.100.106.1521: P 64396777:64397083(306) ack 1905633603 win 368
11:52:58.146419 IP (tos 0x0, ttl 64, id 25005, offset 0, flags [DF], proto: TCP (6), length: 418) 192.168.100.106.1521 > 192.168.90.14.41203: P 1:379(378) ack 306 win 330
11:52:58.147109 IP (tos 0x0, ttl 61, id 37350, offset 0, flags [DF], proto: TCP (6), length: 40) 192.168.90.14.41203 > 192.168.100.106.1521: ., cksum 0x0860 (correct), 306:306(0) ack 379 win 386
11:52:58.148255 IP (tos 0x0, ttl 61, id 37351, offset 0, flags [DF], proto: TCP (6), length: 61) 192.168.90.14.41203 > 192.168.100.106.1521: P, cksum 0xe25b (correct), 306:327(21) ack 379 win 386
11:52:58.148361 IP (tos 0x0, ttl 64, id 25006, offset 0, flags [DF], proto: TCP (6), length: 212) 192.168.100.106.1521 > 192.168.90.14.41203: P 379:551(172) ack 327 win 330
11:52:58.188314 IP (tos 0x0, ttl 61, id 37352, offset 0, flags [DF], proto: TCP (6), length: 40) 192.168.90.14.41203 > 192.168.100.106.1521: ., cksum 0x078d (correct), 327:327(0) ack 551 win 404
---//等待看看:
--//因为网关配置成状态防火墙的形式,从服务端发起的连接都会被拒接..等看看.
--//已经过了200秒,说明client的内核参数tcp_keepalive_*对于连接的服务端无用.也就是client不会主动发起连接测试.
12:07:20.096941 IP (tos 0x0, ttl 64, id 25007, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:20.311391 IP (tos 0x0, ttl 64, id 25008, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:20.742391 IP (tos 0x0, ttl 64, id 25009, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:21.604392 IP (tos 0x0, ttl 64, id 25010, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:23.328394 IP (tos 0x0, ttl 64, id 25011, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:26.777395 IP (tos 0x0, ttl 64, id 25012, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:33.672394 IP (tos 0x0, ttl 64, id 25013, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:07:47.448449 IP (tos 0x0, ttl 64, id 25014, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:08:15.032451 IP (tos 0x0, ttl 64, id 25015, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:09:10.136405 IP (tos 0x0, ttl 64, id 25016, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:11:00.472405 IP (tos 0x0, ttl 64, id 25017, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:13:00.792400 IP (tos 0x0, ttl 64, id 25018, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:15:01.112403 IP (tos 0x0, ttl 64, id 25019, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:17:01.432397 IP (tos 0x0, ttl 64, id 25020, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:19:01.752399 IP (tos 0x0, ttl 64, id 25021, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
12:21:02.072411 IP (tos 0x0, ttl 64, id 25022, offset 0, flags [DF], proto: TCP (6), length: 50) 192.168.100.106.1521 > 192.168.90.14.41203: P, cksum 0x3fee (incorrect (-> 0x01ab), 551:561(10) ack 327 win 330
--//在出现以上数据包过程中,在服务端执行如下:
--//服务器:
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 10 192.168.100.106:1521 192.168.90.14:41203 ESTABLISHED on (52.68/10/0)
..
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 10 192.168.100.106:1521 192.168.90.14:41203 ESTABLISHED on (103.27/12/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 10 192.168.100.106:1521 192.168.90.14:41203 ESTABLISHED on (90.45/12/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 20 192.168.100.106:1521 192.168.90.14:41203 ESTABLISHED on (18446744073.51/14/0)
--//中间不知道为什么冒出这个大的值.
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 20 192.168.100.106:1521 192.168.90.14:41203 ESTABLISHED on (72.29/15/0)
...
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
--//这时连接已经断开在服务端.
--//说明关于netstat -o 参数的解析参考连接:http://blog.itpub.net/267265/viewspace-2138396/
--//The interpretation of field is, first field = timer countdown value, second field = no. of retransmissions,
--//third field = number of keepalive probes sent.
--//可以发现前面的第1字段逐渐减少,而第2字段增加后,第1字段重新记录.
--//客户端:
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 0 192.168.90.14:41203 192.168.100.106:1521 ESTABLISHED off (0.00/0/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 0 192.168.90.14:41203 192.168.100.106:1521 ESTABLISHED off (0.00/0/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 0 192.168.90.14:41203 192.168.100.106:1521 ESTABLISHED off (0.00/0/0)
--//而客户端的连接还在.
--//客户端,在客户端监测:
tcpdump: listening on bond1, link-type EN10MB (Ethernet), capture size 65535 bytes
...
12:27:17.961544 IP (tos 0x0, ttl 64, id 37353, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 64397104:64397410, ack 1905634153, win 404, length 306
12:27:18.166180 IP (tos 0x0, ttl 64, id 37354, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:18.576173 IP (tos 0x0, ttl 64, id 37355, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:19.396154 IP (tos 0x0, ttl 64, id 37356, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:21.036150 IP (tos 0x0, ttl 64, id 37357, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:24.316166 IP (tos 0x0, ttl 64, id 37358, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:30.876176 IP (tos 0x0, ttl 64, id 37359, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:27:43.996189 IP (tos 0x0, ttl 64, id 37360, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:28:10.236177 IP (tos 0x0, ttl 64, id 37361, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:29:02.716433 IP (tos 0x0, ttl 64, id 37362, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:30:47.676172 IP (tos 0x0, ttl 64, id 37363, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:32:47.677461 IP (tos 0x0, ttl 64, id 37364, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:34:47.676459 IP (tos 0x0, ttl 64, id 37365, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:36:47.676446 IP (tos 0x0, ttl 64, id 37366, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:38:47.676172 IP (tos 0x0, ttl 64, id 37367, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
12:40:47.676464 IP (tos 0x0, ttl 64, id 37368, offset 0, flags [DF], proto TCP (6), length 346) 192.168.90.14.41203 > 192.168.100.106.1521: Flags [P.], cksum 0x4116 (incorrect -> 0xfb4b), seq 0:306, ack 1, win 404, length 306
--//同时在客户端执行sql命令:
xxxxx> select sysdate from dual ;
--//挂起..由于服务端连接已经不存在了,最后报如下错误:
*
ERROR at line 1:
ORA-03113: end-of-file on communication channel
Process ID: 6980
Session ID: 6656 Serial number: 50071
--//客户端:
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 306 192.168.90.14:41203 192.168.100.106:1521 ESTABLISHED on (6.85/7/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
tcp 0 306 192.168.90.14:41203 192.168.100.106:1521 ESTABLISHED on (13.09/9/0)
# netstat -otun | egrep 'Active|Proto|192.168.90.14:41203'
Active Internet connections (w/o servers)
Proto Recv-Q Send-Q Local Address Foreign Address State Timer
--//可以看到timer列后面的变化..看到的情况与服务器前面的情况一样.
3.分析时间变化:
12:07:20.096941
11:52:58.188314
--//间隔15*60+20-58 = 862秒,为什么不是SQLNET.EXPIRE_TIME*2分钟=5*2*60 = 600秒呢?
create table t ( a timestamp);
insert into t values ('2018-01-23 12:07:20.096941');
insert into t values ('2018-01-23 12:07:20.311391');
insert into t values ('2018-01-23 12:07:20.742391');
insert into t values ('2018-01-23 12:07:21.604392');
insert into t values ('2018-01-23 12:07:23.328394');
insert into t values ('2018-01-23 12:07:26.777395');
insert into t values ('2018-01-23 12:07:33.672394');
insert into t values ('2018-01-23 12:07:47.448449');
insert into t values ('2018-01-23 12:08:15.032451');
insert into t values ('2018-01-23 12:09:10.136405');
insert into t values ('2018-01-23 12:11:00.472405');
insert into t values ('2018-01-23 12:13:00.792400');
insert into t values ('2018-01-23 12:15:01.112403');
insert into t values ('2018-01-23 12:17:01.432397');
insert into t values ('2018-01-23 12:19:01.752399');
insert into t values ('2018-01-23 12:21:02.072411');
commit;
column interval format 00000.999999
WITH x
AS (SELECT a - n_a interval
FROM ( SELECT a, LAG (a) OVER (ORDER BY a) n_a
FROM t
ORDER BY a)
WHERE n_a IS NOT NULL)
SELECT EXTRACT (DAY FROM interval) * 86400
+ EXTRACT (HOUR FROM interval) * 3600
+ EXTRACT (MINUTE FROM interval) * 60
+ EXTRACT (SECOND FROM interval)
interval
FROM x;
INTERVAL
-------------
00000.214450
00000.431000
00000.862001
00001.724002
00003.449001
00006.894999
00013.776055
00027.584002
00055.103954
00110.336000
00120.319995
00120.320003
00120.319994
00120.320002
00120.320012
15 rows selected.
--//开始间隔0.21秒,以后间隔2倍递增.到110秒后,按照120秒间隔.另外一组数据测试如下,结果惊人的相似.
INTERVAL
-------------
00000.204636
00000.409993
00000.819981
00001.639996
00003.280016
00006.560010
00013.120013
00026.239988
00052.480256
00104.959739
00120.001289
00119.998998
00119.999987
00119.999726
00120.000292
15 rows selected.
--//最大与最小的间隔
WITH x AS (SELECT MAX (a) - MIN (a) interval FROM t)
SELECT SUM
(
EXTRACT (DAY FROM interval) * 86400
+ EXTRACT (HOUR FROM interval) * 3600
+ EXTRACT (MINUTE FROM interval) * 60
+ EXTRACT (SECOND FROM interval)
)
interval_sum
FROM x;
INTERVAL_SUM
------------
809.71492 <== client测试的结果
INTERVAL_SUM
------------
821.97547 <== 服务端测试结果.
--//换一句话讲,如果client端不kill掉,大约需要81X 秒才退出出现提示符号.
--//我这里测试服务端请求认证后的情况,这时服务器连接已经断开,如果在确认期间,客户端执行命令呢? 会发生什么情况呢?看下一篇blog.
--//也许你抱怨无法模拟以上测试,实际上很简单在服务端使用tmux,screen打开会话(这样网络断开,命令可以一直在运行),再执行以上命
--//令,在客户端执行sql语句后,拔掉网线,等待足够的时间就能模拟我的测试结果.
[20180123]测试SQLNET.EXPIRE_TIME参数.txt的更多相关文章
- 转://SQLNET.EXPIRE_TIME参数
DCD: Dead Connection Detection ,可以用于检测.标记僵死而没有断开会session,再由PMON进行清理,释放资源.开启DCD,只需要在服务端的sqlnet.ora文件中 ...
- 使用 SQLNET.EXPIRE_TIME 清除僵死连接
数据库连接的客户端异常断开后,其占有的相应并没有被释放,如从v$session视图中依旧可以看到对应的session处于inactive,且对应的服务器进程也没有释放,导致资源长时间地被占用,对于这种 ...
- [20190211]简单测试端口是否打开.txt
[20190211]简单测试端口是否打开.txt --//昨天看一个链接,提到如果判断一个端口是否打开可以简单执行如下:--//参考链接:https://dba010.com/2019/02/04/c ...
- [20171110]_allow_read_only_corruption参数.txt
[20171110]_allow_read_only_corruption参数.txt --//昨天在修改查询隐含参数脚本时发现一个参数_allow_read_only_corruption,感觉应该 ...
- 【Shared Server Mode】测试调整shared_servers参数对数据库的影响
本文来源于:secooler 的 <[Shared Server Mode]测试调整shared_servers参数对数据库的影响> 关于Shared Server模式的配置方法请参见文 ...
- [20180713]关于hash join 测试中一个疑问.txt
[20180713]关于hash join 测试中一个疑问.txt --//上个星期做的测试,链接: http://blog.itpub.net/267265/viewspace-2157424/-- ...
- maven 测试写入JRE参数
项目在测试时碰到一个问题,就是JVM加载参数的问题. web项目本身在注入配置信息的时候,读取的是本地的配置文件,但是配置文件的位置是卸载tomcat 里面配置的JAVA_OPTS里面的. 问题出现了 ...
- JMeter 压力测试使用CSV参数
表示之前从没用过JMeter所以记录一下使用过程 Apache JMeter是Apache组织开发的基于Java的压力测试工具.用于对软件做压力测试,它最初被设计用于Web应用测试,但后来扩展到其他测 ...
- 测试修改gcs_server_processes参数
RAC部署前提是要求各节点的主机硬件一致的,但实际如果碰上一些不规范的客户,经费有限或是扩容时已买不到同样的机器,那么采购的机器会有一些区别,比如RAC各节点的CPU核数有区别,那么默认的gcs_se ...
随机推荐
- Hexo的next主题安装
通过Git+Hexo搭建的个人博客地址:https://liangh.top/ 1.使用git克隆最新版本 2.先在themes目录创建一个next文件夹,然后在hexo站点目录下右键打开Git Ba ...
- A Painless Q-learning Tutorial (一个 Q-learning 算法的简明教程)
本文是对 http://mnemstudio.org/path-finding-q-learning-tutorial.htm 的翻译,共分两部分,第一部分为中文翻译,第二部分为英文原文.翻译 ...
- maven-assembly-plugin的使用
maven-assembly-plugin使用描述(拷自 maven-assembly-plugin 主页) The Assembly Plugin for Maven is primarily in ...
- Java NIO中的缓冲区Buffer（二）创建/复制缓冲区
创建缓冲区的方式 主要有以下两种方式创建缓冲区: 1.调用allocate方法 2.调用wrap方法 我们将以charBuffer为例,阐述各个方法的含义: allocate方法创建缓冲区 调用all ...
- Deep learning with Python 学习笔记（9）
神经网络模型的优化 使用 Keras 回调函数 使用 model.fit()或 model.fit_generator() 在一个大型数据集上启动数十轮的训练,有点类似于扔一架纸飞机,一开始给它一点推 ...
- NLog日志框架使用探究-1
目录 前言 为什么是NLog? 目的 配置 基本配置 日志等级 输出例子 目标 参数 规则 日志分发 日志收集 结语 参考文档 前言 日志是每个程序的基本模块.本文是为了探究如何通过NLog方便及记录 ...
- MySQL常用的备份方式与备份工具简介
一.MySQL备份方式与备份类型 1.备份的必要性 再生产环境中,为了防止硬件故障.软件故障.自然灾害.误操作等各种原因导致的数据库数据丢失后能恢复到事故之前的状态,我们需要对数据库进行备份和恢复操作 ...
- 牛刀小试MySQL--基于GTID的replication
实验环境:两个MySQL实例 IP地址:10.0.0.201 端口:3306 (MySQL的Master) IP地址:10.0.0.201 端口:3307 (MySQL的Slave) 需要的参数 se ...
- Ado.net和EF的区别
ado.net EF作为微软的一个ORM框架,通过实体.关系型数据库表之间的映射,使开发人员可以通过操作表实体而间接的操作数据库,大大的提高了开发效率.这样一来,.net平台下,我们与底层数据库的交互 ...
- elasticsearch6.7 01.入门指南（1）
Elasticsearch 是一个高度可扩展且开源的全文检索和分析引擎.它可以让您快速.近实时地存储.检索以及分析海量数据.它通常用作那些具有复杂搜索功能和需求的应用的底层引擎或者技术. 下面是 El ...