Question

我想知道在AWS胶水作业加载时是否可以在表格中添加时间戳列。

第一种情景：

A栏| B栏| TimeStamp

A | 2 | 2018-06-03 23：59：00.0

当Crawler更新数据目录中的表并再次运行作业时，该表将使用新的时间戳在表中添加新数据。

A栏| B栏| TimeStamp

A | 4 | 2018-06-04 05：01：31.0

B | 8 | 2018-06-04 06：02：31.0

import sys
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.context import SparkContext
from awsglue.context import GlueContext
from awsglue.job import Job

## @params: [TempDir, JOB_NAME]
args = getResolvedOptions(sys.argv, ['TempDir','JOB_NAME'])

sc = SparkContext()
glueContext = GlueContext(sc)
spark = glueContext.spark_session
job = Job(glueContext)
job.init(args['JOB_NAME'], args)

datasource0 = glueContext.create_dynamic_frame.from_catalog(database = "sampledb", table_name = "abs", transformation_ctx = "datasource0")
applymapping1 = ApplyMapping.apply(frame = datasource0, mappings = [("ColumnA", "char", "ColumnA", "char"), ("ColumnB", "char", "ColumnB", "char")], transformation_ctx = "applymapping1")
resolvechoice2 = ResolveChoice.apply(frame = applymapping1, choice = "make_cols", transformation_ctx = "resolvechoice2")
dropnullfields3 = DropNullFields.apply(frame = resolvechoice2, transformation_ctx = "dropnullfields3")
datasink4 = glueContext.write_dynamic_frame.from_jdbc_conf(frame = dropnullfields3, catalog_connection = "TESTDB", connection_options = {"dbtable": "TABLEA", "database": "anasightprd01"}, redshift_tmp_dir = args["TempDir"], transformation_ctx = "datasink4")

Answer 1

将DynamicFrame转换为spark的DataFrame，添加一个包含当前时间戳的新列，然后在写入之前将其转换回DynamicFrame。

import sys
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.context import SparkContext
from awsglue.context import GlueContext, DynamicFrame
from awsglue.job import Job
from pyspark.sql.functions import current_timestamp

## @params: [TempDir, JOB_NAME]
args = getResolvedOptions(sys.argv, ['TempDir','JOB_NAME'])

sc = SparkContext()
glueContext = GlueContext(sc)
spark = glueContext.spark_session
job = Job(glueContext)
job.init(args['JOB_NAME'], args)

datasource0 = glueContext.create_dynamic_frame.from_catalog(database = "sampledb", table_name = "abs", transformation_ctx = "datasource0")
applymapping1 = ApplyMapping.apply(frame = datasource0, mappings = [("ColumnA", "char", "ColumnA", "char"), ("ColumnB", "char", "ColumnB", "char")], transformation_ctx = "applymapping1")
resolvechoice2 = ResolveChoice.apply(frame = applymapping1, choice = "make_cols", transformation_ctx = "resolvechoice2")
dropnullfields3 = DropNullFields.apply(frame = resolvechoice2, transformation_ctx = "dropnullfields3")
# add TimeStamp column
timestampedDf = dropnullfields3.toDF().withColumn("TimeStamp", current_timestamp())
timestamped4 = DynamicFrame.fromDF(timestampedDf, glueContext, "timestampedDf")
datasink4 = glueContext.write_dynamic_frame.from_jdbc_conf(frame = timestamped4, catalog_connection = "TESTDB", connection_options = {"dbtable": "TABLEA", "database": "anasightprd01"}, redshift_tmp_dir = args["TempDir"], transformation_ctx = "datasink4")

这里你的Python代码应该是这样的：

{{1}}

Answer 2

虽然可能有一种方法可以在胶水代码中获取当前日期时间，但另一种在插入时为数据添加时间戳的常用方法是将一个TIMESTAMP数据列添加到Redshift表中，该表绑定到默认值GETDATE()

CREATE TABLE myschema.mytable
(
    ... OTHER Fields here
    insertedtimestamp TIMESTAMP WITH TIME ZONE DEFAULT(GETDATE())
);

插入的技巧是确保insertedtimestamp或INSERT INTO字段中未指定COPY列 - 因为行已添加到表中

INSERT INTO myschema.mytable(Col1, Col2 ...) -- NB no `insertedtimestamp` column
VALUES ('col1', 'col2' ...);

- insertedtimestamp的值将自动加盖时间戳

使用AWS Glue Job在redshift中导入数据时添加时间戳列

2 个答案: