随笔分类 - Hive1.4
摘要:根据mapjoin的计算原理,MAPJION会把小表全部读入内存中,在map阶段直接拿另外一个表的数据和内存中表数据做匹配。这种情况下即使笛卡尔积也不会对任务运行速度造成太大的效率影响。mapjoin的应用场景如下:1.有一个极小的表= a.min_dt) f left outer join h...
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摘要:Status of Hive Authorization before Hive 0.13SQL Standards Based HiveAuthorization (New in Hive 0.13)Restrictions on HiveCommands and StatementsPrivil...
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摘要:Hive Concurrency ModelHive Concurrency ModelUse CasesTurn Off ConcurrencyDebuggingConfigurationLocking in Hive TransactionsUse CasesConcurrency suppor...
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摘要:EXPLAIN SyntaxEXPLAIN SyntaxHive provides anEXPLAINcommand that shows the execution plan for a query. The syntax for this statement is as follows:EXPL...
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摘要:LanguageManual WindowingAndAnalyticsSkip to end of metadataAdded byLefty Leverenz, last edited byLefty Leverenzon Aug 01, 2014(view change)show commen...
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摘要:Virtual ColumnsSimple ExamplesVirtual ColumnsHive 0.8.0 provides support for two virtual columns:One isINPUT__FILE__NAME, which is the input file's na...
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摘要:Sampling SyntaxSampling Bucketized TableBlock SamplingSampling Syntax 抽样语法Sampling Bucketized Tabletable_sample: TABLESAMPLE (BUCKET x OUT OF y [ON co...
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摘要:Subqueries in the FROM ClauseSubqueries in the WHERE ClauseSubqueries in the FROM ClauseSELECT...FROM(subquery)name...SELECT...FROM(subquery)ASname......
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摘要:Lateral View SyntaxDescriptionExampleMultiple Lateral ViewsOuter Lateral ViewsLateral View SyntaxlateralView: LATERAL VIEW udtf(expression) tableAlias...
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摘要:Union Syntaxselect_statement UNION ALL select_statement UNION ALL select_statement ...UNION is used to combine the result from multiple SELECT stateme...
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摘要:Join OptimizationJoin OptimizationImprovements to the Hive OptimizerStar Join OptimizationStar Schema ExamplePrior Support for MAPJOINLimitations of P...
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摘要:Hive JoinsHive JoinsJoin SyntaxExamplesMapJoin RestrictionsJoin OptimizationPredicate Pushdown in Outer JoinsEnhancements in Hive Version 0.11Join Syn...
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摘要:Documentation for Built-In User-Defined Functions Related To XPathUDFsxpath, xpath_short, xpath_int, xpath_long, xpath_float, xpath_double, xpath_numb...
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摘要:Hive Operators and User-Defined Functions (UDFs)Hive Operators and User-Defined Functions (UDFs)Built-in OperatorsRelational OperatorsArithmetic Opera...
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摘要:Transform/Map-Reduce SyntaxSQL Standard Based Authorization Disallows TRANSFORMTRANSFORM ExamplesSchema-less Map-reduce ScriptsTyping the output of TR...
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摘要:Syntax of Order BySyntax of Sort ByDifference between Sort By and Order BySetting Types for Sort BySyntax of Cluster By and Distribute BySyntax of Ord...
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摘要:Group By SyntaxSimple ExamplesSelect statement and group by clauseAdvanced FeaturesMulti-Group-By InsertsMap-side Aggregation for Group ByGrouping Set...
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摘要:Select SyntaxWHERE ClauseALL and DISTINCT ClausesPartition Based QueriesHAVING ClauseLIMIT ClauseREGEX Column SpecificationMore Select SyntaxGROUP BYS...
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摘要:LanguageManual ImportExportSkip to end of metadataAdded byCarl Steinbach, last edited byLefty Leverenzon May 14, 2013(view change)show commentGo to st...
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摘要:LanguageManual DMLHive Data Manipulation LanguageHive Data Manipulation LanguageLoading files into tablesSyntaxSynopsisNotesInserting data into Hive T...
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