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1. 今天遇到一个错误，在连接到 hive 之后，无法执行任何命令。
$ beeline -u “jdbc:hive2://hostname.domain.cn:10000/default;principal=hive/_HOST@domain.com;”
Connecting to jdbc:hive2://hostname.domain.cn:10000/default;principal=hive/_HOST@domain.com;
Connected to: Apache Hive (version release-1.2.1-EDH-1.1.2)
Driver: Hive JDBC (version release-1.2.1-EDH-1.1.2)
Transaction isolation: TRANSACTION_REPEATABLE_READ
Beeline version release-1.2.1-EDH-1.1.2 by Apache Hive
0: jdbc:hive2://hostname.domain.cn:10000> show databases;
返回错误如下
Error: Error while processing statement: FAILED: Execution Error, return code 1 from org.apache.Hadoop.hive.ql.exec.DDLTask. MetaException
(message:For direct MetaStore DB connections, we don’t support retries at the client level.) (state=08S01,code=1)
2. 百度这个错误，很多文档都提及是字符集的问题，需要保证 mysql 的字符集是 latin1.
mysql> show variables like ‘%collation_%’;
+———————-+——————-+
| Variable_name | Value |
+———————-+——————-+
| collation_connection | latin1_swedish_ci |
| collation_database | latin1_swedish_ci |
| collation_server | latin1_swedish_ci |
+———————-+——————-+
3. 如果字符集不是 latin1，需要手动执行 (本次问题，不是这个，我的字符集，原本就是 latin1)
mysql>use hive
mysql>alter database hive character set latin1;
4. 后来尝试重启一下 hive，结果，metastore 竟然启动失败。查看日志，说创建表失败。这个 hive 已经运行一段时间了，一直没有问题。对应的表也都是存在的，没有道理重建的。
5. 日志输出如下：
Traceback (most recent call last):
File “/var/lib/ambari-agent/cache/common-services/HIVE/0.12.0.2.0/package/scripts/hive_metastore.py”, line 259, in <module>
HiveMetastore().execute()
File “/usr/lib/python2.6/site-packages/resource_management/libraries/script/script.py”, line 280, in execute
method(env)
File “/var/lib/ambari-agent/cache/common-services/HIVE/0.12.0.2.0/package/scripts/hive_metastore.py”, line 59, in start
self.configure(env)
File “/var/lib/ambari-agent/cache/common-services/HIVE/0.12.0.2.0/package/scripts/hive_metastore.py”, line 73, in configure
hive(name = ‘metastore’)
File “/usr/lib/python2.6/site-packages/ambari_commons/os_family_impl.py”, line 89, in thunk
return fn(*args, **kwargs)
File “/var/lib/ambari-agent/cache/common-services/HIVE/0.12.0.2.0/package/scripts/hive.py”, line 320, in hive
user = params.hive_user
File “/usr/lib/python2.6/site-packages/resource_management/core/base.py”, line 155, in __init__
self.env.run()
File “/usr/lib/python2.6/site-packages/resource_management/core/environment.py”, line 160, in run
self.run_action(resource, action)
File “/usr/lib/python2.6/site-packages/resource_management/core/environment.py”, line 124, in run_action
provider_action()
File “/usr/lib/python2.6/site-packages/resource_management/core/providers/system.py”, line 273, in action_run
tries=self.resource.tries, try_sleep=self.resource.try_sleep)
File “/usr/lib/python2.6/site-packages/resource_management/core/shell.py”, line 71, in inner
result = function(command, **kwargs)
File “/usr/lib/python2.6/site-packages/resource_management/core/shell.py”, line 93, in checked_call
tries=tries, try_sleep=try_sleep)
File “/usr/lib/python2.6/site-packages/resource_management/core/shell.py”, line 141, in _call_wrapper
result = _call(command, **kwargs_copy)
File “/usr/lib/python2.6/site-packages/resource_management/core/shell.py”, line 294, in _call
raise Fail(err_msg)
resource_management.core.exceptions.Fail: Execution of ‘export HIVE_CONF_DIR=/usr/hdp/current/hive-metastore/conf/conf.server ; /usr/hdp/current/hive-metastore/bin/schematool -initSchema -dbType mysql -userName hive -passWord [PROTECTED] -verbose’ returned 1. Metastore connection URL: jdbc:mysql://hostname.mysql.cn/hivemeta
Metastore Connection Driver : com.mysql.jdbc.Driver
Metastore connection User: hive
Starting metastore schema initialization to 1.2.0
Initialization script hive-schema-1.2.0.mysql.sql
Connecting to jdbc:mysql://hostname.mysql.cn/hivemeta
Connected to: MySQL (version 5.1.73)
Driver: MySQL Connector Java (version mysql-connector-java-5.1.40 ( Revision: 402933ef52cad9aa82624e80acbea46e3a701ce6))
Transaction isolation: TRANSACTION_READ_COMMITTED
0: jdbc:mysql://hostname.mysql.cn/hivem> !autocommit on
Autocommit status: true
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET @OLD_CHARACTER_SET_C
LIENT=@@CHARACTER_SET_CLIENT */
No rows affected (0.003 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET @OLD_CHARACTER_SET_R
ESULTS=@@CHARACTER_SET_RESULTS */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET @OLD_COLLATION_CONNE
CTION=@@COLLATION_CONNECTION */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET NAMES utf8 */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40103 SET @OLD_TIME_ZONE=@@TIM
E_ZONE */
No rows affected (0.002 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40103 SET TIME_ZONE=’+00:00′ *
/
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40014 SET @OLD_UNIQUE_CHECKS=@
@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40014 SET @OLD_FOREIGN_KEY_CHE
CKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */
No rows affected (0.001 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET @OLD_SQL_MODE=@@SQL_
MODE, SQL_MODE=’NO_AUTO_VALUE_ON_ZERO’ */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40111 SET @OLD_SQL_NOTES=@@SQL
_NOTES, SQL_NOTES=0 */
No rows affected (0.001 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET @saved_cs_client
= @@character_set_client */
No rows affected (0 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> /*!40101 SET character_set_client
= utf8 */
No rows affected (0.001 seconds)
0: jdbc:mysql://hostname.mysql.cn/hivem> CREATE TABLE IF NOT EXISTS `BUCKE
TING_COLS` (`SD_ID` bigint(20) NOT NULL, `BUCKET_COL_NAME` varchar(256) CHARACT
ER SET latin1 COLLATE latin1_bin DEFAULT NULL, `INTEGER_IDX` int(11) NOT NULL, P
RIMARY KEY (`SD_ID`,`INTEGER_IDX`), KEY `BUCKETING_COLS_N49` (`SD_ID`), CONSTRAI
NT `BUCKETING_COLS_FK1` FOREIGN KEY (`SD_ID`) REFERENCES `SDS` (`SD_ID`) ) ENGIN
E=InnoDB DEFAULT CHARSET=latin1
Error: Can’t create table ‘hivemeta.bucketing_cols’ (errno: 121) (state=HY000,code=1005)
Closing: 0: jdbc:mysql://hostname.mysql.cn/hivemeta
org.apache.hadoop.hive.metastore.HiveMetaException: Schema initialization FAILED! Metastore state would be inconsistent !!
org.apache.hadoop.hive.metastore.HiveMetaException: Schema initialization FAILED! Metastore state would be inconsistent !!
at org.apache.hive.beeline.HiveSchemaTool.doInit(HiveSchemaTool.java:270)
at org.apache.hive.beeline.HiveSchemaTool.doInit(HiveSchemaTool.java:243)
at org.apache.hive.beeline.HiveSchemaTool.main(HiveSchemaTool.java:473)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.run(RunJar.java:221)
at org.apache.hadoop.util.RunJar.main(RunJar.java:136)
Caused by: java.io.IOException: Schema script failed, errorcode 2
at org.apache.hive.beeline.HiveSchemaTool.runBeeLine(HiveSchemaTool.java:358)
at org.apache.hive.beeline.HiveSchemaTool.runBeeLine(HiveSchemaTool.java:326)
at org.apache.hive.beeline.HiveSchemaTool.doInit(HiveSchemaTool.java:266)
… 8 more
*** schemaTool failed ***
6. 根据关键字“Schema initialization FAILED! Metastore state would be inconsistent !!”，查询到 hdp 的官方论坛。
解释说，这个是一个已知的问题。需要修改 ambari 的 sql 脚本，删除 mysql 的一些 index 等。
https://community.hortonworks.com/questions/113748/hive-metastore-start.html
7. 官方建议的步骤繁多。个人比较懒。而且这个 hive 库，前一天还是正常的。这个问题是突然出现的，我不倾向与，这个是 bug 的可能。
继续分析，查看 hivemetastore 的 log，还是有必要的。
发现问题，表不存在
2018-03-07 15:34:43,871 INFO [pool-8-thread-200]: metastore.HiveMetaStore (HiveMetaStore.java:logInfo(746)) – 200: get_all_databases
2018-03-07 15:34:43,871 INFO [pool-8-thread-200]: HiveMetaStore.audit (HiveMetaStore.java:logAuditEvent(371)) – ugi=ambari-qa-hbjt_hadoop@domain.com ip=/172.18.98.57 cmd=get_all_databases
2018-03-07 15:34:43,873 ERROR [pool-8-thread-200]: metastore.RetryingHMSHandler (RetryingHMSHandler.java:invoke(165)) – HMSHandler Fatal error: javax.jdo.JDOException: Exception thrown when executing query
at org.datanucleus.api.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:596)
……
NestedThrowablesStackTrace:
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Table ‘hivemeta.dbs’ doesn’t exist
at sun.reflect.GeneratedConstructorAccessor60.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
8. 现在要从 mysql 入手分析，逐步检查。
mysql> use hive
mysql> show tables;
+—————————+
| Tables_in_hivemeta |
+—————————+
| BUCKETING_COLS |
| CDS |
| COLUMNS_V2 |
| COMPACTION_QUEUE |
| COMPLETED_TXN_COMPONENTS |
| DATABASE_PARAMS |
| DBS |
| DB_PRIVS |
| DELEGATION_TOKENS |
9. 问题来了，表不存在。为什么不存在呢？其实我已经知道问题了。Mysql 表名大小写敏感问题。
mysql>select count(*) from `DBS`;
ERROR 1146 (42S02): Table ‘hivemeta.DBS’ doesn’t exist
10. 由于很多 Oracle 数据库的表名是大小写不敏感的。但是 Mysql 却是表名大小写敏感的。所以，很多开发人员，都喜欢将 mysql 设置为表名大小写不敏感。
而 show tables 之后，我就怀疑这个可能了。
11. 经过检查 /etc/my.cnf，确实已经设置 lower_case_table_names=1
12. Hive 库创建的时候，mysql 是大小写敏感的。所以，表名都是大写的。而后期，有人修改了 mysql 参数，取消大小写敏感。这样，问题就来了。Mysql 并不是完全不敏感，而是在设置参数 lower_case_table_names=1 之后，创建和查询的 sql 语句中的表名，默认修改为小写的。而已经创建的表名，还是大写的显示。但是你无论用大写表名，还是小写表名，都无法正确查询到了。
13. 这个问题出现的场景：
只有是在 hive 库创建完成之后，又修改 /etc/my.cnf，添加参数 lower_case_table_names= 1 导致的。
14. 问题找到之后，有两个解决方案：
a. 取消参数 lower_case_table_names=1
b. 如果 mysql 的 hive 库中没有什么数据，删除 hive 库表，重新创建 hive meta 表，直接就创建出小写的表名了。
输出就是小写的了：
mysql> show tables;
+—————————+
| Tables_in_hive_beta |
+—————————+
| bucketing_cols |
| cds |
| columns_v2 |
| compaction_queue |
| completed_txn_components |
| database_params |
| db_privs |
| dbs |
| delegation_tokens |
| func_ru |
15. 我最后选择取消参数 lower_case_table_names=1，并重启 mysql。查询正常了。
mysql> select count(*) from `DBS`;
+———-+
| count(*) |
+———-+
| 2 |
16. Ambari 启动 hive metastore 也成功了。
问题解决，一切恢复正常
$ beeline -u “jdbc:hive2://hostname.domain.cn:10000/default;principal=hive/_HOST@domain.com;”
Connecting to jdbc:hive2://hostname.domain.cn:10000/default;principal=hive/_HOST@domain.com;
Connected to: Apache Hive (version release-1.2.1-EDH-1.1.2)
Driver: Hive JDBC (version release-1.2.1-EDH-1.1.2)
Transaction isolation: TRANSACTION_REPEATABLE_READ
Beeline version release-1.2.1-EDH-1.1.2 by Apache Hive
0: jdbc:hive2://hostname.domain.cn:10000> show databases;
+—————-+–+
| database_name |
+—————-+–+
| default |
| hbjt |
+—————-+–+
2 rows selected (1.206 seconds)
最终的原因，就是有人修改的 /etc/my.cnf，导致的本次问题。
