Simo, Author at Simon Technology Blog

Hibernate – If Cascade.Persist and Cascade.Remove are used together in the parent entity in the HiberNet, Cascade deletes don’t work.

I have a table relationship definition as shown below, I am trying to cascade persistence and delete from Entity2 (table 2) means deleting a record from table2 should delete the entry in table 3, a

October 12, 2021By Simo Hibernate Cascade, Cascade.Pascade, Cascade.remove, Casual, entity, father, Hibernate, Hibernet, if, Perscade, removeLeave a Comment

Hadoop-HDFS-Storage Model – Architecture Model – Role Introduction

October 12, 2021By Simo Hadoop architecture, Hadoop, HDFS, Introduction, model, role, storageLeave a Comment

How CouchBase achieves powerful consistency

I searched for an explanation of how Couchbase achieves strong consistency within the cluster. Are all these results of using membase? Couchbase IS membase btw. Couchbase IS membase btw. Couchba

October 12, 2021By Simo Hadoop Consistency, Couchbase, How, implement, powerfulLeave a Comment

Hive Digital Client Interface Tool

1. Hive’s official website introduces three graphical interface tools that can connect to HiveServer2 through JDBC in Windows, including: SQuirrel SQL Client, Oracle SQL Developer and DbVisualizer.

October 12, 2021By Simo Hadoop client, hive, Interface, Number, tool, warehouseLeave a Comment

Hibernate – JPA @LOB attribute encoding cannot be used with PostgreSQL text

JPA Mapping

I am using JPA and Hibernate. I have an entity with @Lob attributes

@Column(nullable=false)
@Lob
private String text; I am using PostgreSQL 8.4 and entities are correctly ma

October 12, 2021By Simo Hibernate attribute, can't, encoding, Hibernate, JPA, LOB, PostgreSQL, Text, Together, useLeave a Comment

Why happened to hadoop spilling?

I am very new to the Hadoop system and the learning phase.

I noticed that Spill occurs as long as the MapOutputBuffer reaches 80% in the Shuffle and Sort phases (I think this can also be conf

October 12, 2021By Simo Hadoop Hadoop, spilling, why, will occurLeave a Comment

Hadoop – excludes partition fields from the selection query in Hive

Suppose I have the following table definition in Hive (the actual table has about 65 columns):

CREATE EXTERNAL TABLE S .TEST (
COL1 STRING,
COL2 STRING
)
PARTITIONED BY (extract_date STRING

October 12, 2021By Simo Hadoop fields, SubzaLeave a Comment

Hibernate tools are erroneous in Eclipse STS when connecting to mySQL database

I use Eclipse STS 3.1.0 and Hibernate Tools 3.6.0. I am trying to connect to a MySQL 5.5 database to generate my DAO class. I am using the MySQL driver mysql-connector- java-5.1.21.jar

When s

October 12, 2021By Simo Hibernate database, Eclipse, mysql, STSLeave a Comment

Hadoop uses Java to set FSPERMISSION to DIR in recursive way

Hi I have a test program, load the file to hdfs user/user1/data/app/type/file.gz on this path now this test program is run multiple times by multiple users . So I want to set the file permissions t

October 12, 2021By Simo Hadoop DIR, FSPERMISSION, Hadoop, Java, Recurns, setting, wayLeave a Comment

HIVE common statement

1Hive Introduction Hive to me is a data warehouse based on HDFS, which provides a type of SQL language (it is basically the same as the SQL standard but has some special differences) , Allows engi

October 12, 2021By Simo Hadoop common, hive, statementLeave a Comment