之前遇到的一个drop table的小问题，默认任何人都可以有使用drop db.table的权限
这是一个bug,
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bugid:https://issues.apache.org/jira/browse/HIVE-2817
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解决方法：
可以通过设置
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set hive.exec.drop.ignorenonexistent=false（Do not report an error if DROP TABLE/VIEW specifies a non-existent table/view,
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这个值默认是true，
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DROPIGNORESNONEXISTENT("hive.exec.drop.ignorenonexistent", true)
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）来解决。
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Workaround:
set hive.exec.drop.ignorenonexistent=false.
Before that,
we need to check all the "drop" sqls and change to drop if exists.
we need to remove all "drop table db.table" syntax to "use db; drop table if exists table;"
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但是如果设置了hive.exec.drop.ignorenonexistent=false，如果表xxx不存在，drop table xxx会报错
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hive> set hive.exec.drop.ignorenonexistent=false;
hive> drop table tt;
FAILED: SemanticException [Error 10001]: Table not found tt
hive> set hive.exec.drop.ignorenonexistent=true;
hive> drop table tt;
OK
Time taken: 0.055 seconds
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另外，drop db.table这种语法也会报错，如果设置hive.exec.drop.ignorenonexistent为true则不会报错
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hive> set hive.exec.drop.ignorenonexistent=true;
hive> drop table cdnlog.ttt;
FAILED: SemanticException [Error 10001]: Table not found cdnlog.ttt
hive> use cdnlog;drop table ttt;
OK
Time taken: 0.042 seconds
OK
set hive.exec.drop.ignorenonexistent=true;
hive> drop table cdnlog.ttt;
OK
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因为更改etl sql的代价比较大，因此只能把hive.exec.drop.ignorenonexistent设置为true，另外需要fix这个bug
drop table是ddl操作，对应的analyzer相关类的路径为：
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ql/src/java/org/apache/hadoop/hive/ql/parse/DDLSemanticAnalyzer.java
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对应的方法是analyzeDropTable：
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@@ -
721
,
13
+
716
,
30
@@
private
void
analyzeDropTable(ASTNode ast,
boolean
expectView)
throws
SemanticException {
String tableName = getUnescapedName((ASTNode) ast.getChild(
0
));
boolean
ifExists = (ast.getFirstChildWithType(HiveParser.TOK_IFEXISTS) !=
null
);
// we want to signal an error if the table/view doesn't exist and we're
// configured not to fail silently
boolean
throwException =
!ifExists && !HiveConf.getBoolVar(conf, ConfVars.DROPIGNORESNONEXISTENT);
try
{
- Table tab = db.getTable(db.getCurrentDatabase(), tableName, throwException);
+
// to fix the drop table bug
+ String tableName2 =
""
;
+
if
(tableName.contains(
"."
)) {
+
try
{
+ tableName2 = tableName.split(
"\\."
)[
1
];
+ }
catch
(Exception e) {
+
// do nothing if tableName can't be splitted
+ tableName2 = tableName;
+ }
+ }
else
{
+ tableName2 = tableName;
+ }
+ Table tab = db.getTable(db.getCurrentDatabase(), tableName2, throwException);
+
+
// Table tab = db.getTable(db.getCurrentDatabase(), tableName, throwException);
+
if
(tab !=
null
) {
inputs.add(
new
ReadEntity(tab));
outputs.add(
new
WriteEntity(tab));
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本文转自菜菜光 51CTO博客，原文链接：http://blog.51cto.com/caiguangguang/1558885，如需转载请自行联系原作者
