使用S3A文件系统作为数据源，并在AWS Glue作业脚本中指定相应的选项。代码示例：

from pyspark.context import SparkContext
from pyspark.sql.session import SparkSession
from awsglue.context import GlueContext
from awsglue.dynamicframe import DynamicFrame
from awsglue.transforms import *
from awsglue.utils import getResolvedOptions
from pyspark.sql.functions import *

sc = SparkContext.getOrCreate()
glueContext = GlueContext(sc)
spark = SparkSession.builder.appName("MyApp").getOrCreate()

# Specify S3A as the file system
sc.hadoopConfiguration.set("fs.s3a.impl", "org.apache.hadoop.fs.s3a.S3AFileSystem")

# Get the S3 path for the data source
args = getResolvedOptions(sys.argv, ['s3_source_path'])

# Read data from the S3 source using S3A
df = spark.read.format("csv").option("header", "true").load(args['s3_source_path'])

# Perform the MERGE INTO query
df.write.mode("overwrite").insertInto("my_database.my_table")