Hive是如何解析SQL的呢,首先拿hive的建表语句来举例,比如下面的建表语句
create table test(id int,name string)row format delimited fields terminated by '\t';
然后使用hive的show create table语句来查看创建的表结构，这是一张text表
CREATE TABLE `test`( `id` int, `name` string) ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe' WITH SERDEPROPERTIES ( 'field.delim'='\t', 'serialization.format'='\t') STORED AS INPUTFORMAT 'org.apache.hadoop.mapred.TextInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat' LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'transient_lastDdlTime'='1568561230')
当然还有其他各种建表语句，比如
csv表
CREATE EXTERNAL TABLE `default.test_1`( `key` string COMMENT 'from deserializer', `value` string COMMENT 'from deserializer') ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.OpenCSVSerde' WITH SERDEPROPERTIES ( 'escapeChar'='\\', 'quoteChar'='\'', 'separatorChar'='\t') STORED AS INPUTFORMAT 'org.apache.hadoop.mapred.TextInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat' LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'COLUMN_STATS_ACCURATE'='false', 'numFiles'='0', 'numRows'='-1', 'rawDataSize'='-1', 'totalSize'='0', 'transient_lastDdlTime'='xxxx')
parquet表
CREATE TABLE `default.test`( `time` string, `server` int, `id` bigint) PARTITIONED BY ( `ds` string) ROW FORMAT SERDE 'org.apache.hadoop.hive.ql.io.parquet.serde.ParquetHiveSerDe' WITH SERDEPROPERTIES ( 'field.delim'='\t', 'serialization.format'='\t') STORED AS INPUTFORMAT 'org.apache.hadoop.hive.ql.io.parquet.MapredParquetInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.parquet.MapredParquetOutputFormat' LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'transient_lastDdlTime'='xxxx')
json表
CREATE EXTERNAL TABLE `default.test`( `titleid` string COMMENT 'from deserializer', `timestamp` string COMMENT 'from deserializer') ROW FORMAT SERDE 'org.openx.data.jsonserde.JsonSerDe' STORED AS INPUTFORMAT 'org.apache.hadoop.mapred.TextInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat' LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'COLUMN_STATS_ACCURATE'='false', 'numFiles'='0', 'numRows'='-1', 'rawDataSize'='-1', 'totalSize'='0',
es表
CREATE EXTERNAL TABLE `default.test`( `id` string COMMENT 'from deserializer', `ts` string COMMENT 'from deserializer', ') PARTITIONED BY ( `ds` string) ROW FORMAT SERDE 'org.elasticsearch.hadoop.hive.EsSerDe' STORED BY 'org.elasticsearch.hadoop.hive.EsStorageHandler' WITH SERDEPROPERTIES ( 'serialization.format'='1') LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'es.index.auto.create'='yes', 'es.index.read.missing.as.empty'='yes', 'es.nodes'='host1,host2', 'es.port'='9200', 'es.resource'='index1/type1',
使用thrift的binary表
CREATE EXTERNAL TABLE `default.test`( `bbb` string COMMENT 'from deserializer', `aaa` string COMMENT 'from deserializer') COMMENT 'aas' PARTITIONED BY ( `ds` string COMMENT '日期分区') ROW FORMAT SERDE 'org.apache.hadoop.hive.serde2.thrift.ThriftDeserializer' WITH SERDEPROPERTIES ( 'serialization.class'='com.xxx.xxx.xxx.tables.v1.XXXX', 'serialization.format'='org.apache.thrift.protocol.TCompactProtocol') STORED AS INPUTFORMAT 'org.apache.hadoop.mapred.SequenceFileInputFormat' OUTPUTFORMAT 'org.apache.hadoop.hive.ql.io.HiveSequenceFileOutputFormat' LOCATION 'hdfs://master:8020/user/hive/warehouse/test' TBLPROPERTIES ( 'transient_lastDdlTime'='xxxxxx')
hbase表
CREATE EXTERNAL TABLE default.hbase_table(key string, k1 string,k2 string,k3 string,k4 string,ts string)
ROW FORMAT SERDE
'org.apache.hadoop.hive.hbase.HBaseSerDe'
STORED BY
'org.apache.hadoop.hive.hbase.HBaseStorageHandler'
WITH SERDEPROPERTIES ("hbase.columns.mapping"=":key,c:k1,c:k2,c:k3,c:k4,c:ts")
TBLPROPERTIES("hbase.table.name" = "xxxxx");
等等
可以查看show create table的hive源码
https://github.com/apache/hive/blob/68ae4a5cd1b916098dc1deb2bcede5f862afd80e/ql/src/java/org/apache/hadoop/hive/ql/ddl/table/creation/ShowCreateTableOperation.java
其中可以看出hive表的一些基本信息
private static final String CREATE_TABLE_TEMPLATE =
"CREATE <" + TEMPORARY + "><" + EXTERNAL + ">TABLE `<" + NAME + ">`(\n" +
"<" + LIST_COLUMNS + ">)\n" +
"<" + COMMENT + ">\n" +
"<" + PARTITIONS + ">\n" +
"<" + BUCKETS + ">\n" +
"<" + SKEWED + ">\n" +
"<" + ROW_FORMAT + ">\n" +
"<" + LOCATION_BLOCK + ">" +
"TBLPROPERTIES (\n" +
"<" + PROPERTIES + ">)\n";
private String getCreateTableCommand(Table table) {
ST command = new ST(CREATE_TABLE_TEMPLATE);
command.add(NAME, desc.getTableName());
command.add(TEMPORARY, getTemporary(table));
command.add(EXTERNAL, getExternal(table));
command.add(LIST_COLUMNS, getColumns(table));
command.add(COMMENT, getComment(table));
command.add(PARTITIONS, getPartitions(table));
command.add(BUCKETS, getBuckets(table));
command.add(SKEWED, getSkewed(table));
command.add(ROW_FORMAT, getRowFormat(table));
command.add(LOCATION_BLOCK, getLocationBlock(table));
command.add(PROPERTIES, getProperties(table));
return command.render();
}
当用户输入一行create table语句的时候,可查看源码
https://github.com/apache/hive/blob/ff98efa7c6f2b241d8fddd0ac8dc55e817ecb234/ql/src/java/org/apache/hadoop/hive/ql/parse/ParseUtils.java
美团点评 Hive SQL的编译过程
https://tech.meituan.com/2014/02/12/hive-sql-to-mapreduce.html
其中可以看到,建表语句首先会使用antlr4将其转换成一颗语法树
public static ASTNode parse(String command) throws ParseException {
return parse(command, null);
}
然后可以使用getTable抽取其中的库名和表名
https://github.com/apache/hive/blob/f37c5de6c32b9395d1b34fa3c02ed06d1bfbf6eb/ql/src/java/org/apache/hadoop/hive/ql/parse/AnalyzeCommandUtils.java
源码
public static Table getTable(ASTNode tree, BaseSemanticAnalyzer sa) throws SemanticException {
String tableName = ColumnStatsSemanticAnalyzer.getUnescapedName((ASTNode) tree.getChild(0).getChild(0));
String currentDb = SessionState.get().getCurrentDatabase();
String [] names = Utilities.getDbTableName(currentDb, tableName);
return sa.getTable(names[0], names[1], true);
}
https://github.com/apache/hive/blob/master/ql/src/java/org/apache/hadoop/hive/ql/parse/ParseDriver.java
public ASTNode parse(String command) throws ParseException {
return parse(command, null);
}
然后比如要提取inputformat，outpurformat，serde和storageHandler
https://github.com/apache/hive/blob/f37c5de6c32b9395d1b34fa3c02ed06d1bfbf6eb/ql/src/java/org/apache/hadoop/hive/ql/parse/StorageFormat.java
源码
要提取字段信息，SkewedValue，表名以及row format
https://github.com/apache/hive/blob/f37c5de6c32b9395d1b34fa3c02ed06d1bfbf6eb/ql/src/java/org/apache/hadoop/hive/ql/parse/BaseSemanticAnalyzer.java
源码
public static List<FieldSchema> getColumns(
ASTNode ast, boolean lowerCase, TokenRewriteStream tokenRewriteStream,
List<SQLPrimaryKey> primaryKeys, List<SQLForeignKey> foreignKeys,
List<SQLUniqueConstraint> uniqueConstraints, List<SQLNotNullConstraint> notNullConstraints,
List<SQLDefaultConstraint> defaultConstraints, List<SQLCheckConstraint> checkConstraints,
Configuration conf) throws SemanticException {
我是源码
}
源码
/**
* Get the unqualified name from a table node.
*
* This method works for table names qualified with their schema (e.g., "db.table")
* and table names without schema qualification. In both cases, it returns
* the table name without the schema.
*
* @param node the table node
* @return the table name without schema qualification
* (i.e., if name is "db.table" or "table", returns "table")
*/
public static String getUnescapedUnqualifiedTableName(ASTNode node) {
assert node.getChildCount() <= 2;
if (node.getChildCount() == 2) {
node = (ASTNode) node.getChild(1);
}
return getUnescapedName(node);
}
源码
protected void analyzeRowFormat(ASTNode child) throws SemanticException {
child = (ASTNode) child.getChild(0);
int numChildRowFormat = child.getChildCount();
for (int numC = 0; numC < numChildRowFormat; numC++) {
ASTNode rowChild = (ASTNode) child.getChild(numC);
switch (rowChild.getToken().getType()) {
case HiveParser.TOK_TABLEROWFORMATFIELD:
fieldDelim = unescapeSQLString(rowChild.getChild(0)
.getText());
if (rowChild.getChildCount() >= 2) {
fieldEscape = unescapeSQLString(rowChild
.getChild(1).getText());
}
break;
case HiveParser.TOK_TABLEROWFORMATCOLLITEMS:
collItemDelim = unescapeSQLString(rowChild
.getChild(0).getText());
break;
case HiveParser.TOK_TABLEROWFORMATMAPKEYS:
mapKeyDelim = unescapeSQLString(rowChild.getChild(0)
.getText());
break;
case HiveParser.TOK_TABLEROWFORMATLINES:
lineDelim = unescapeSQLString(rowChild.getChild(0)
.getText());
if (!lineDelim.equals("\n")
&& !lineDelim.equals("10")) {
throw new SemanticException(SemanticAnalyzer.generateErrorMessage(rowChild,
ErrorMsg.LINES_TERMINATED_BY_NON_NEWLINE.getMsg()));
}
break;
case HiveParser.TOK_TABLEROWFORMATNULL:
nullFormat = unescapeSQLString(rowChild.getChild(0)
.getText());
break;
default:
throw new AssertionError("Unkown Token: " + rowChild);
}
}
}
}
分区信息，首先通过取得Map对象，
https://github.com/apache/hive/blob/6f18bbbc2e030ce7d446b2475037203cbd4f860d/ql/src/java/org/apache/hadoop/hive/ql/parse/AnalyzeCommandUtils.java
源码
public static Map<String,String> getPartKeyValuePairsFromAST(Table tbl, ASTNode tree,
HiveConf hiveConf) throws SemanticException {
ASTNode child = ((ASTNode) tree.getChild(0).getChild(1));
Map<String,String> partSpec = new HashMap<String, String>();
if (child != null) {
partSpec = DDLSemanticAnalyzer.getValidatedPartSpec(tbl, child, hiveConf, false);
} //otherwise, it is the case of analyze table T compute statistics for columns;
return partSpec;
}
再转换成List<Partition>对象
https://github.com/apache/hive/blob/556531182dc989e12fd491d951b353b4df13fd47/ql/src/java/org/apache/hadoop/hive/ql/parse/BaseSemanticAnalyzer.java
源码
public Map<String, String> partSpec; // has to use LinkedHashMap to enforce order
public List<Partition> partitions; // involved partitions in TableScanOperator/FileSinkOperator partitions = db.getPartitions(table, partSpec);
location信息，parsedLocation
https://github.com/apache/hive/blob/0213afb8a31af1f48d009edd41cec9e6c8942354/ql/src/java/org/apache/hadoop/hive/ql/parse/ImportSemanticAnalyzer.java
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