FAILED TO READ MORROR SIDE 1 问题描述: 环境: RAC p740 p550 -bash-3.2$ srvctl status database -d kmis Instance kmis1 is running on node p550 Instance kmis2 is not running on node p740 AIX -bash-3.2$ oslevel -r 6100-08 数据库 oracle 11.2.2
FAILED TO READ MORROR SIDE 1
问题描述:
环境:
RAC p740 p550
-bash-3.2$ srvctl status database -d kmis
Instance kmis1 is running on node p550
Instance kmis2 is not running on node p740
AIX
-bash-3.2$ oslevel -r
6100-08
数据库 oracle 11.2.2
$ srvctl start database -d kmis
PRCR-1079 : Failed to start resource ora.kmis.db
CRS-5017: The resource action "ora.ARCHDG.dg start" encountered the following error:
ORA-15032: not all alterations performed
ORA-15017: diskgroup "ARCHDG" cannot be mounted
ORA-15063: ASM discovered an insufficient number of disks for diskgroup "ARCHDG"
ORA-15080: synchronous I/O operation to a disk failed
CRS-2674: Start of 'ora.ARCHDG.dg' on 'p740' failed
CRS-2632: There are no more servers to try to place resource 'ora.kmis.db' on that would satisfy its placement policy
$
$ srvctl start instance -d kmis -i kmis2 -o open;
PRCR-1013 : Failed to start resource ora.kmis.db
PRCR-1064 : Failed to start resource ora.kmis.db on node p740
CRS-5017: The resource action "ora.ARCHDG.dg start" encountered the following error:
ORA-15032: not all alterations performed
ORA-15017: diskgroup "ARCHDG" cannot be mounted
ORA-15063: ASM discovered an insufficient number of disks for diskgroup "ARCHDG"
ORA-15080: synchronous I/O operation to a disk failed
1
p550
ASMCMD> ls -lState Type Rebal NameMOUNTED EXTERN N ARCHDG/MOUNTED NORMAL N CRS/MOUNTED EXTERN N DATADG/ASMCMD> host
p740上
MOUNTED NORMAL N CRS/MOUNTED EXTERN N DATADG/挂载不上 ARCDG
一挂载就报错
odm:
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|
B - Defect | 12.1 | ||
2 - Severe Loss of Service | 11.2.0.1 | ||
90 - Closed, Verified by Filer | 212 - IBM AIX on POWER Systems (64-bit) | ||
2010-12-22 | |||
2014-3-19 | N/A | ||
11.2.0.1 | Generic | ||
Oracle |

|
Oracle Database Products | Oracle Database Suite | ||
Oracle Database | 5 - Oracle Database - Enterprise Edition | ||

Hdr: 10422126 11.2.0.1 RDBMS 11.2.0.1 ASM PRODID-5 PORTID-212 Abstract: FAILED TO READ MORROR SIDE 1 <strong>*** 12/22/10 03:46 am ***</strong> ---- PROBLEM: -------- Alert log spooling this error continously and filling up available space. Here is the message. ----------------------- WARNING: failed to read mirror side 1 of virtual extent 665 logical extent 0 of file 280 in group [1.445758315] from disk ASM_ESBQA001_DATA1_0005 allocation unit 75811 reason error; if possible,will try another mirror side ----------------------- When the problem starts, errors spin in the alert log until disk space is exausted. We have found that the process that is refrenced in the trace is usually an orphaned ebiz form. Recent Changes - Upgrade to 11.2.0.1 Over the weekend we have upgraded Production Database to 11.2.0.1. We've had 2 occurrence of the issue on 2 of the RAC nodes. The issue had happened in QA and we have tried to drop the disk and add new disk again, but it did not solve the problem. One more thing to note is, when this happens, there was a "run-away" process that also generates the same error message in a trace file. As long as that session/process is killed, the error messages stops. Please investigate. DIAGNOSTIC ANALYSIS: -------------------- This looks closely related to bug.10051315 and bug.10055063 But customer has applied these patches already, even then we still see the same warning messages. We are still trying to get information from customer to understand how that session is being killed(not sure could be from database end --or application end). Customer confirmed the following : --------------- 1.) Are they in-house scripts scheduled in database/os which are going to kill the inactive sessions at database/os level ? -- There are not any scripts scheduled to kill sessions. When this error starts happening, we kill the process manually. 2.) Is this happening only during specific intervals. -- I cannot see a pattern as to when it is happening. It seems random. 3.) Please confirm - the ASM instance is functional (one can connect to it, run queries on the various v$asm% views, like: v$asm_diskgroup, v$asm_disk) -- Yes, ASM is functional during the error. All other sessions continue to run without errors. --------------- WORKAROUND: ----------- As long as that session/process is killed, the error messages stops. RELATED BUGS: ------------- bug.10051315 and bug.10055063 REPRODUCIBILITY: ---------------- Its random. TEST CASE: ---------- NA STACK TRACE: ------------ Function List (to Full stack) (to Summary stack) ksedsts <- ksdxfstk <- ksdxcb <- sspuser <- f0 <- sdbgrfucf_close_file <- sdbgrfcf_close_file <- dbgrlWriteTextOnly <- dbgrlWriteAlertDetail_int <- dbgrlWriteAlertDetail <- dbgrlWriteAlertText <- dbkrlWriteAlertText <- dbkrlPril <- ksdfmw <- ksdwrt <- kfioCompleteIO <- kfioWaitIO <- kfioRequestPriv <- kfioRequest <- ksfd_kfioRequest <- ksfd_osmio <- ksfd_io <- ksfdread <- kcfrbd1 <- kcbzib <- kcbgcur <- kturRollbackToSavepoint <- ktcrsp1 <- ksures <- ksuxds <- kssdel <- kssdch <- ksudlp <- opidcl <- opidrv <- sou2o <- opimai_real <- ssthrdmain <- main SUPPORTING INFORMATION: ----------------------- Customer’s Management name: Al Fischer Customer's Management 24x7 contact number: +1-616-648-6244 Customer’s Management email: al.fischer@amway.com Primary Customer Email address: eric.lai Secondary Contact Name: George Zhang Secondary Contact Email: (EMAIL ADDRESS) george.zhang@alticor.com 24 HOUR CONTACT INFORMATION FOR P1 BUGS: ---------------------------------------- DIAL-IN INFORMATION: -------------------- IMPACT DATE: ------------ " system at risk of crashing as alert logging is filling up; causing forms to hang at Call Center" <strong>*** 12/22/10 03:57 am ***</strong> <strong>*** 12/22/10 04:20 am ***</strong> <strong>*** 12/22/10 04:21 am ***</strong> <strong>*** 12/22/10 04:21 am *** (CHG: Sta->16)</strong> <strong>*** 12/22/10 04:33 am ***</strong> <strong>*** 12/22/10 05:35 am ***</strong> <strong>*** 12/22/10 06:08 am ***</strong> <strong>*** 12/22/10 06:09 am ***</strong> <strong>*** 12/22/10 06:10 am ***</strong> <strong>*** 12/22/10 08:06 am ***</strong> <strong>*** 12/22/10 11:25 am *** </strong> <strong>*** 12/22/10 11:25 am ***</strong> <strong>*** 12/22/10 01:47 pm *** (CHG: Sta->10)</strong> <strong>*** 12/22/10 01:47 pm ***</strong> <strong>*** 12/22/10 07:46 pm ***</strong> <strong>*** 12/22/10 07:58 pm ***</strong> File versions form GI & RDBMS homes. Below is the info from GI_HOME. [usax02w] $ ar -t -v -X32_64 $GI_HOME/lib/libserver11.a kfd.o rw-rw-rw- 10000/1026 393236 Nov 15 13:29 2010 kfd.o [usax02w] $ ar -t -v -X32_64 $GI_HOME/lib/libserver11.a kfdp.o rw-rw-rw- 10000/1026 271741 Nov 15 13:29 2010 kfdp.o [usax02w] $ ar -t -v -X32_64 $GI_HOME/lib/libserver11.a kfkio.o rw-rw-rw- 10000/1026 103575 Nov 15 13:29 2010 kfkio.o [usax02w] $ ar -t -v -X32_64 $GI_HOME/lib/libserver11.a kfksubs.o rw-rw-rw- 10000/1026 166215 Nov 15 13:29 2010 kfksubs.o Below is the info from RDBMS_HOME [usax02w] $ echo $ORACLE_HOME /u01/apps/oracle/product/11.2.0/db_1 [usax02w] $ ar -t -v -X32_64 $ORACLE_HOME/lib/libserver11.a kfd.o rw-rw-rw- 10000/1026 393236 Nov 15 13:29 2010 kfd.o [usax02w] $ ar -t -v -X32_64 $ORACLE_HOME/lib/libserver11.a kfdp.o rw-rw-rw- 10000/1026 271741 Nov 15 13:29 2010 kfdp.o [usax02w] $ ar -t -v -X32_64 $ORACLE_HOME/lib/libserver11.a kfkio.o rw-rw-rw- 10000/1026 103575 Nov 15 13:29 2010 kfkio.o [usax02w] $ ar -t -v -X32_64 $ORACLE_HOME/lib/libserver11.a kfksubs.o rw-rw-rw- 10000/1026 166215 Nov 15 13:29 2010 kfksubs.o Regards, Prathap <strong>*** 12/22/10 08:01 pm *** (CHG: Sta->16)</strong> <strong>*** 12/22/10 08:25 pm ***</strong> <strong>*** 12/23/10 01:48 am ***</strong> <strong>*** 12/23/10 02:46 am ***</strong> <strong>*** 12/23/10 06:25 am *** (CHG: Sta->11)</strong> <strong>*** 12/23/10 06:25 am ***</strong> <strong>*** 12/23/10 06:26 am *** </strong> <strong>*** 12/23/10 06:26 am ***</strong> <strong>*** 12/24/10 01:43 am *** </strong> <strong>*** 12/24/10 01:43 am ***</strong> <strong>*** 12/27/10 11:33 am ***</strong> <strong>*** 12/27/10 11:45 am ***</strong> <strong>*** 12/27/10 11:51 am ***</strong> <strong>*** 12/27/10 12:22 pm *** ESCALATED</strong> <strong>*** 12/27/10 12:22 pm ***</strong> <strong>*** 12/27/10 12:29 pm ***</strong> <strong>*** 12/28/10 12:42 am *** (CHG: Sta->30)</strong> <strong>*** 12/28/10 12:42 am ***</strong> <strong>*** 12/28/10 05:00 am *** (CHG: Sta->16)</strong> <strong>*** 12/28/10 05:00 am ***</strong> <strong>*** 12/28/10 05:08 am *** (CHG: Sta->11)</strong> <strong>*** 12/28/10 09:37 am ***</strong> <strong>*** 12/29/10 02:51 am ***</strong> <strong>*** 12/31/10 03:05 am ***</strong> <strong>*** 01/02/11 08:28 pm ***</strong> <strong>*** 01/04/11 01:43 am *** (CHG: Sta->30)</strong> <strong>*** 01/04/11 01:43 am ***</strong> <strong>*** 01/04/11 01:54 am ***</strong> <strong>*** 01/04/11 04:50 am *** (CHG: Sta->11)</strong> <strong>*** 01/04/11 04:50 am ***</strong> <strong>*** 01/05/11 01:26 am *** (CHG: Sta->30)</strong> <strong>*** 01/05/11 01:26 am ***</strong> <strong>*** 01/10/11 10:46 am ***</strong> <strong>*** 01/10/11 10:46 am *** (CHG: Sta->11)</strong> <strong>*** 01/11/11 03:14 am ***</strong> <strong>*** 01/13/11 11:32 pm ***</strong> RELEASE NOTES: ]] kfk SO is deleted, while there are still allocated sessions. REDISCOVERY INFORMATION: The following error, even with fix 10051315: WARNING: IO Failed. group:1 disk(number.incarnation):5.0xe0d14bb7 disk_path:/dev/ASM_1457_4 AU:75811 disk_offset(bytes):79494299648 io_size:8192 operation:Read type:synchronous result:I/O error process_id:2338940 subsys:System iop:0x110939310 bufp:0x70000016f2ec000 osderr:0x434c5344 osderr1:0x0 WORKAROUND: None <strong>*** 01/13/11 11:44 pm *** </strong> <strong>*** 01/13/11 11:44 pm *** </strong> <strong>*** 01/13/11 11:44 pm *** (CHG: Sta->80)</strong> <strong>*** 01/16/11 11:05 pm ***</strong> <strong>*** 01/16/11 11:17 pm ***</strong> <strong>*** 01/16/11 11:36 pm ***</strong> <strong>*** 01/17/11 12:01 am ***</strong> <strong>*** 01/17/11 07:09 am ***</strong> <strong>*** 01/17/11 07:11 am ***</strong> <strong>*** 01/17/11 09:25 am ***</strong> <strong>*** 01/17/11 10:16 am ***</strong> <strong>*** 01/17/11 11:14 pm ***</strong> <strong>*** 01/18/11 05:06 am ***</strong> <strong>*** 01/18/11 11:47 am ***</strong> <strong>*** 01/18/11 11:52 pm ***</strong> <strong>*** 01/19/11 02:05 am ***</strong> <strong>*** 01/19/11 05:39 am ***</strong> <strong>*** 01/19/11 05:45 am ***</strong> <strong>*** 01/19/11 07:43 am ***</strong> <strong>*** 01/19/11 08:44 am ***</strong> <strong>*** 01/19/11 06:12 pm ***</strong> <strong>*** 01/19/11 06:14 pm ***</strong> <strong>*** 01/19/11 10:53 pm ***</strong> <strong>*** 01/20/11 12:11 am ***</strong> <strong>*** 01/20/11 04:04 am ***</strong> <strong>*** 01/20/11 06:11 am ***</strong> <strong>*** 01/20/11 06:59 am ***</strong> <strong>*** 01/20/11 09:13 am ***</strong> <strong>*** 01/20/11 10:44 am ***</strong> <strong>*** 01/20/11 10:44 am ***</strong> <strong>*** 01/20/11 11:00 am ***</strong> <strong>*** 01/20/11 11:38 am ***</strong> <strong>*** 01/20/11 04:58 pm ***</strong> <strong>*** 01/21/11 04:05 am ***</strong> <strong>*** 01/24/11 11:33 am ***</strong> <strong>*** 01/25/11 02:17 am ***</strong> <strong>*** 01/27/11 02:58 am ***</strong> <strong>*** 01/27/11 03:16 am ***</strong> <strong>*** 01/27/11 03:37 am ***</strong> <strong>*** 01/27/11 03:49 am ***</strong> <strong>*** 02/02/11 04:37 am ***</strong> <strong>*** 02/04/11 08:25 pm ***</strong> <strong>*** 02/05/11 02:46 am ***</strong> <strong>*** 02/05/11 02:58 am ***</strong> <strong>*** 02/05/11 02:59 am ***</strong> <strong>*** 02/05/11 02:29 pm ***</strong> <strong>*** 02/05/11 07:19 pm ***</strong> <strong>*** 02/05/11 09:37 pm ***</strong> <strong>*** 02/07/11 01:37 am ***</strong> <strong>*** 02/07/11 06:14 am ***</strong> <strong>*** 02/07/11 12:35 pm ***</strong> <strong>*** 02/07/11 06:46 pm ***</strong> <strong>*** 02/07/11 08:33 pm ***</strong> <strong>*** 02/08/11 01:52 pm ***</strong> <strong>*** 02/08/11 02:42 pm ***</strong> <strong>*** 02/08/11 10:32 pm ***</strong> <strong>*** 02/09/11 11:51 pm ***</strong> <strong>*** 02/10/11 08:56 am ***</strong> <strong>*** 02/10/11 08:59 am ***</strong> <strong>*** 02/10/11 09:30 am ***</strong> <strong>*** 02/11/11 11:52 pm ***</strong> <strong>*** 02/12/11 05:10 pm ***</strong> <strong>*** 02/15/11 02:55 am ***</strong> <strong>*** 02/15/11 10:13 am ***</strong> <strong>*** 02/16/11 01:07 am ***</strong> <strong>*** 02/16/11 06:34 am ***</strong> <strong>*** 02/18/11 01:39 am ***</strong> <strong>*** 02/18/11 01:40 am ***</strong> <strong>*** 02/24/11 07:20 am ***</strong> <strong>*** 02/24/11 07:35 am ***</strong> <strong>*** 02/25/11 12:34 am ***</strong> <strong>*** 03/02/11 07:59 am ***</strong> <strong>*** 03/02/11 08:25 am ***</strong> <strong>*** 03/03/11 01:22 am ***</strong> <strong>*** 03/03/11 03:34 pm ***</strong> <strong>*** 03/07/11 11:54 am ***</strong> <strong>*** 03/08/11 08:53 pm ***</strong> <strong>*** 03/09/11 10:44 pm ***</strong> <strong>*** 04/20/11 01:17 pm ***</strong> <strong>*** 04/21/11 09:34 am ***</strong> <strong>*** 04/21/11 01:46 pm ***</strong> <strong>*** 04/22/11 03:47 pm ***</strong> <strong>*** 04/29/11 12:33 pm ***</strong> <strong>*** 04/29/11 01:21 pm ***</strong> <strong>*** 05/02/11 07:53 am ***</strong> <strong>*** 05/03/11 01:12 am ***</strong> <strong>*** 05/03/11 01:37 am ***</strong> <strong>*** 05/03/11 02:11 am ***</strong> <strong>*** 05/11/11 03:00 am ***</strong> <strong>*** 05/11/11 03:44 am ***</strong> <strong>*** 05/16/11 08:07 am ***</strong> <strong>*** 05/17/11 11:31 am ***</strong> <strong>*** 05/17/11 11:34 am ***</strong> <strong>*** 05/17/11 03:14 pm ***</strong> <strong>*** 05/17/11 03:16 pm ***</strong> <strong>*** 05/18/11 06:00 am ***</strong> <strong>*** 05/18/11 06:11 am ***</strong> <strong>*** 05/18/11 08:46 am ***</strong> <strong>*** 06/09/11 12:44 pm ***</strong> <strong>*** 06/10/11 10:21 am ***</strong> <strong>*** 06/10/11 10:21 am ***</strong> <strong>*** 06/11/11 04:44 am ***</strong> <strong>*** 06/14/11 10:14 pm ***</strong> <strong>*** 06/17/11 12:33 pm ***</strong> <strong>*** 07/04/11 01:09 pm ***</strong> <strong>*** 07/06/11 04:03 pm ***</strong> <strong>*** 07/06/11 04:56 pm ***</strong> <strong>*** 07/08/11 11:47 am ***</strong> <strong>*** 07/08/11 12:16 pm ***</strong> <strong>*** 07/12/11 07:28 am ***</strong> <strong>*** 07/14/11 07:58 pm *** </strong> <strong>*** 07/17/11 05:29 am ***</strong> <strong>*** 07/17/11 05:30 am ***</strong> <strong>*** 07/18/11 03:23 pm ***</strong> <strong>*** 07/26/11 03:20 pm ***</strong> <strong>*** 07/26/11 03:23 pm ***</strong> <strong>*** 07/27/11 03:13 am ***</strong> <strong>*** 07/27/11 03:15 am ***</strong> <strong>*** 07/27/11 07:33 am ***</strong> <strong>*** 08/02/11 01:34 pm ***</strong> <strong>*** 08/03/11 01:03 am *** </strong> <strong>*** 08/03/11 01:03 am ***</strong> <strong>*** 08/03/11 01:15 am *** </strong> <strong>*** 08/03/11 01:15 am ***</strong> <strong>*** 08/05/11 08:00 am ***</strong> <strong>*** 08/05/11 08:11 am ***</strong> <strong>*** 08/05/11 10:42 am ***</strong> <strong>*** 08/11/11 01:22 am ***</strong> <strong>*** 08/12/11 04:00 am ***</strong> <strong>*** 08/12/11 10:03 am ***</strong> <strong>*** 08/18/11 12:46 pm ***</strong> <strong>*** 08/22/11 12:14 pm ***</strong> <strong>*** 09/07/11 04:49 am ***</strong> <strong>*** 09/09/11 02:55 pm ***</strong> <strong>*** 09/14/11 02:40 pm ***</strong> <strong>*** 10/14/11 02:15 am ***</strong> <strong>*** 10/14/11 02:15 am *** ESCALATION -> CLOSED</strong> <strong>*** 10/14/11 02:15 am *** (CHG: Sta->90)</strong> <strong>*** 10/14/11 02:21 am *** </strong> <strong>*** 10/14/11 02:21 am ***</strong> <strong>*** 10/14/11 09:56 am ***</strong> <strong>*** 11/01/11 01:55 am ***</strong> <strong>*** 11/01/11 10:49 am ***</strong> <strong>*** 11/01/11 10:49 am ***</strong> <strong>*** 11/27/11 01:15 am ***</strong> <strong>*** 12/01/11 09:11 am ***</strong> <strong>*** 01/17/12 03:29 pm ***</strong> <strong>*** 01/23/12 08:26 pm ***</strong> <strong>*** 01/23/12 08:26 pm ***</strong> <strong>*** 03/14/12 01:07 am ***</strong> <strong>*** 03/18/12 11:22 pm ***</strong> <strong>*** 03/22/12 12:44 am ***</strong> <strong>*** 04/02/12 06:10 am ***</strong> <strong>*** 04/24/12 10:45 am ***</strong> <strong>*** 01/26/13 08:03 am ***</strong> <strong>*** 01/31/13 07:35 am ***</strong> <strong>*** 02/24/13 11:27 pm ***</strong> <strong>*** 04/16/13 02:14 am ***</strong> <strong>*** 04/19/13 07:23 am ***</strong> <strong>*** 05/12/13 09:12 pm ***</strong> <strong>*** 05/20/13 06:28 am ***</strong> <strong>*** 06/25/13 01:16 am ***</strong> <strong>*** 07/08/13 09:41 pm ***</strong> <strong>*** 07/09/13 09:44 pm ***</strong> <strong>*** 07/09/13 10:24 pm ***</strong> <strong>*** 07/17/13 03:02 am ***</strong> <strong>*** 07/18/13 02:35 am ***</strong> <strong>*** 08/12/13 03:54 am ***</strong> <strong>*** 08/20/13 12:21 am ***</strong> <strong>*** 09/30/13 12:26 pm ***</strong> <strong>*** 10/23/13 05:08 pm ***</strong> <strong>*** 10/29/13 08:22 am ***</strong> <strong>*** 10/29/13 09:56 am ***</strong> <strong>*** 10/29/13 09:56 am ***</strong> <strong>*** 12/18/13 03:38 am ***</strong> <strong>*** 01/23/14 09:24 pm ***</strong> <strong>*** 02/11/14 09:58 am ***</strong> <strong>*** 02/24/14 03:11 am ***</strong> <strong>*** 02/24/14 06:02 am ***</strong> <strong>*** 02/24/14 12:34 pm ***</strong> <strong>*** 02/24/14 03:58 pm ***</strong> <strong>*** 02/25/14 02:28 am ***</strong> <strong>*** 03/18/14 04:34 am ***</strong> <strong>*** 03/18/14 04:55 am ***</strong> <strong>*** 03/18/14 05:09 am ***</strong> <strong>*** 03/18/14 10:37 pm ***</strong> <strong>*** 03/19/14 12:39 am ***</strong>

掌握添加MySQL用戶的方法對於數據庫管理員和開發者至關重要,因為它確保數據庫的安全性和訪問控制。 1)使用CREATEUSER命令創建新用戶,2)通過GRANT命令分配權限,3)使用FLUSHPRIVILEGES確保權限生效,4)定期審計和清理用戶賬戶以維護性能和安全。

chosecharforfixed-lengthdata,varcharforvariable-lengthdata,andtextforlargetextfield.1)chariseffity forconsistent-lengthdatalikecodes.2)varcharsuitsvariable-lengthdatalikenames,ballancingflexibilitibility andperformance.3)

在MySQL中處理字符串數據類型和索引的最佳實踐包括:1)選擇合適的字符串類型,如CHAR用於固定長度,VARCHAR用於可變長度,TEXT用於大文本;2)謹慎索引,避免過度索引,針對常用查詢創建索引;3)使用前綴索引和全文索引優化長字符串搜索;4)定期監控和優化索引,保持索引小巧高效。通過這些方法,可以在讀取和寫入性能之間取得平衡,提升數據庫效率。

ToaddauserremotelytoMySQL,followthesesteps:1)ConnecttoMySQLasroot,2)Createanewuserwithremoteaccess,3)Grantnecessaryprivileges,and4)Flushprivileges.BecautiousofsecurityrisksbylimitingprivilegesandaccesstospecificIPs,ensuringstrongpasswords,andmonitori

tostorestringsefliceflicyInmySql,ChooSetherightDataTypeBasedyOrneOrneEds:1)USEcharforFixed-LengthStstringStringStringSlikeCountryCodes.2)UseVarcharforvariable-lengtthslikenames.3)USETEXTCONTENT.3)

選擇MySQL的BLOB和TEXT數據類型時,BLOB適合存儲二進制數據,TEXT適合存儲文本數據。 1)BLOB適用於圖片、音頻等二進制數據,2)TEXT適用於文章、評論等文本數據,選擇時需考慮數據性質和性能優化。

No,youshouldnotusetherootuserinMySQLforyourproduct.Instead,createspecificuserswithlimitedprivilegestoenhancesecurityandperformance:1)Createanewuserwithastrongpassword,2)Grantonlynecessarypermissionstothisuser,3)Regularlyreviewandupdateuserpermissions

mySqlStringDatatAtatPessHouldBechoseBasedondatActarActeristicsAndusecases:1)USEcharforFixed lengthStstringStringStringSlikeCountryCodes.2)usevarcharforvariable-lengtthslikeLikenames.3)usebarnionororvarinyorvarinyorvarybinarydatalgebenedaTalgeextocrabextrapon.4)


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