Bumped spring boot to 2.4.0.

Default server port is now 9090.
Added data-jdbc-plain.
Reduced contention level to zero by default (configurable via cli).

Author: kai-niemi

README.md

@@ -7,13 +7,15 @@ stack composed by Spring Boot, Spring Data and Spring HATEOAS.
 Data access variants include:
 
 - [JDBC](roach-data-jdbc/README.md) - using Spring Data JDBC 
+- [JDBC (plain)](roach-data-jdbc-plain/README.md) - using plain JDBC 
 - [JPA](roach-data-jpa/README.md) - using Spring Data JPA with Hibernate as ORM provider 
 - [jOOQ](roach-data-jooq/README.md) - using Spring Boot with jOOQ (not officially supported by spring-data) 
 - [MyBatis](roach-data-mybatis/README.md) - using Spring Data MyBatis/JDBC
+- [JSON](roach-data-json/README.md) - using Spring Data JPA and JSONB types with inverted indexes
 
-All demos are independent and use the same schema and test workload. 
+Most demos are independent and use the same schema and test workload. 
 
-Common Spring Boot features in all demos:
+Common Spring Boot features demonstrated:
 
 - Liquibase Schema versioning
 - Hikari Connection Pool
@@ -23,8 +25,8 @@ Common Spring Boot features in all demos:
 - Hypermedia API via Spring HATEOAS and HAL media type
 - Simple HTTP client invoking commands
 
-The most documented demo is the JDBC version. It includes an extra aspect for setting transaction attributes such 
-as time travel / follower reads. 
+The most documented demo is the JDBC version. It includes an extra aspect for setting transaction 
+attributes such timeouts and read-only hints. 
 
 ## Prerequisites
 
@@ -40,27 +42,34 @@ See each respective module for more details.
 
 ## Running 
 
-All demos do the same thing which is to run through a series of concurrent account
-transfer requests. The requests are being intentionally submitted in such a way 
-it will cause lock contention in the database and thereby trigger aborts and retry's. 
-That's why the demo starts with a wall of warning messages, which is expected.
-It ends with the message:
+All demos do the same thing, which is to run through a series of concurrent account
+transfer requests. The requests are being intentionally submitted in a way that 
+will cause lock contention in the database and trigger aborts and retry's. 
 
-    "All client workers finished but server keeps running. Have a nice day!" 
+By default, the contention level is zero (serial execution) so you won't see any errors. 
+To observe these errors, pass a number (>1) to the command line representing the thread count. 
+Then you will see transaction conflicts and retries on the server side until the demo 
+settles with an end message:
+
+    "All client workers finished but server keeps running. Have a nice day!"
 
 The service remains running after the test is complete and can be access via: 
 
-- http://localhost:8080
+- http://localhost:9090
 
 You could use something like Postman to send requests to the API on your own.
 
 A custom database URL is specified with a config override:
 
-    --spring.datasource.url=jdbc:postgresql://192.168.1.99:26257/roach_data?sslmode=disable
+    --spring.datasource.url=jdbc:postgresql://192.168.1.123:26257/roach_data?sslmode=disable
 
 ### JDBC demo
 
-    java -jar roach-data-jdbc/target/roach-data-jdbc.jar 
+    java -jar roach-data-jdbc/target/roach-data-jdbc.jar
+
+with contention:
+
+    java -jar roach-data-jdbc/target/roach-data-jdbc.jar 8
 
 ### JPA demo
 

pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
-        <version>2.3.5.RELEASE</version>
+        <version>2.4.0</version>
         <relativePath/> <!-- lookup parent from repository -->
     </parent>
 
@@ -20,8 +20,9 @@
     </properties>
 
     <modules>
-        <module>roach-data-jooq</module>
         <module>roach-data-jdbc</module>
+        <module>roach-data-jdbc-plain</module>
+        <module>roach-data-jooq</module>
         <module>roach-data-jpa</module>
         <module>roach-data-json</module>
         <module>roach-data-mybatis</module>
@@ -32,7 +33,7 @@
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-starter-web</artifactId>
-                <version>2.3.4.RELEASE</version>
+                <version>2.4.0</version>
                 <exclusions>
                     <!-- Exclude the Tomcat dependency -->
                     <exclusion>
@@ -47,6 +48,11 @@
                 <version>3.8.9</version>
                 <scope>runtime</scope>
             </dependency>
+            <dependency>
+                <groupId>net.ttddyy</groupId>
+                <artifactId>datasource-proxy</artifactId>
+                <version>1.7</version>
+            </dependency>
         </dependencies>
     </dependencyManagement>
 

roach-data-jdbc-plain/README.md

@@ -0,0 +1,3 @@
+# Roach Demo Data :: Plain JDBC
+
+A CockroachDB demo using only JDBC for data access.

roach-data-jdbc-plain/pom.xml

@@ -0,0 +1,44 @@
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xmlns="http://maven.apache.org/POM/4.0.0"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>io.roach.data</groupId>
+        <artifactId>roach-data-parent</artifactId>
+        <version>1.0.0.BUILD-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>roach-data-jdbc-plain</artifactId>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-api</artifactId>
+            <version>1.7.30</version>
+        </dependency>
+        <dependency>
+            <groupId>org.slf4j</groupId>
+            <artifactId>slf4j-simple</artifactId>
+            <version>1.7.30</version>
+            <scope>provided</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>com.zaxxer</groupId>
+            <artifactId>HikariCP</artifactId>
+            <version>3.4.5</version>
+        </dependency>
+        <dependency>
+            <groupId>org.postgresql</groupId>
+            <artifactId>postgresql</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>net.ttddyy</groupId>
+            <artifactId>datasource-proxy</artifactId>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <finalName>roach-data-jdbc-plain</finalName>
+    </build>
+</project>