Trying to reuse Spring JdbcTemplate connection for Postgres JDBC copyIn - getting 'relation does not exist' - spring

Question

I've hit a brick wall in a Spring/Kotlin/JDBC/Postgres project and am hoping the community can help.
What I'm Trying To Do
Use Spring JDBC API (JdbcTemplate) to create a temporary table (temporary_pokemon) in a Postgres database.
Unwrap the JDBC connection from the JdbcTemplate so I can use the same connection to load a CSV into the database using the Postgres JDBC driver's copyIn method (https://jdbc.postgresql.org/documentation/publicapi/org/postgresql/copy/CopyIn.html)
What Is Going Wrong
The copyIn method errors with the message relation "temporary_pokemon" does not exist, and my assumption here is that the unwrapped connection is somehow separate/different to the db.execute command which creates the table.
Ideally there's a way to re-use the same connection while still being able to rely largely on Spring Boot's autoconfiguration and things like automatic connection pooling, etc.
What I've Tried So Far
Adding the #Transactional annotation
Creating a DataSource manually using Spring Boot's DataSourceBuilder (this seems to work, I am assuming that it only creates a single connection which gets reused)
The error message
Caused by: org.postgresql.util.PSQLException: ERROR: relation "temporary_pokemon" does not exist
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2553) ~[postgresql-42.2.18.jar:42.2.18]
at org.postgresql.core.v3.QueryExecutorImpl.processCopyResults(QueryExecutorImpl.java:1212) ~[postgresql-42.2.18.jar:42.2.18]
at org.postgresql.core.v3.QueryExecutorImpl.startCopy(QueryExecutorImpl.java:894) ~[postgresql-42.2.18.jar:42.2.18]
at org.postgresql.copy.CopyManager.copyIn(CopyManager.java:45) ~[postgresql-42.2.18.jar:42.2.18]
at org.postgresql.copy.CopyManager.copyIn(CopyManager.java:177) ~[postgresql-42.2.18.jar:42.2.18]
at org.postgresql.copy.CopyManager.copyIn(CopyManager.java:160) ~[postgresql-42.2.18.jar:42.2.18]
at com.example.demo.IngestPostgres.ingest(IngestPostgres.kt:32) ~[main/:na]
at com.example.demo.IngestPostgres$$FastClassBySpringCGLIB$$f1321c17.invoke(<generated>) ~[main/:na]
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.2.jar:5.3.2]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:771) ~[spring-aop-5.3.2.jar:5.3.2]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.2.jar:5.3.2]
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:749) ~[spring-aop-5.3.2.jar:5.3.2]
... 14 common frames omitted
Code Snippets
My #Component for the CommandLineRunner:
#Component
class Seed : CommandLineRunner {
#Autowired
lateinit var ingester : IngestPostgres
override fun run(vararg args: String?) {
val buffer = BufferedReader(FileReader(File("src/main/resources/ingest.csv")))
ingester.ingest(buffer)
}
}
The IngestPostgres #Component:
#Component
class IngestPostgres {
#Autowired
private lateinit var db: JdbcTemplate
#Transactional
fun ingest(bufferedReader: BufferedReader) {
db.execute("""
DROP TABLE IF EXISTS temporary_pokemon;
CREATE TABLE temporary_pokemon (
pokemon_id INT,
pokemon_name VARCHAR,
pokemon_type VARCHAR
);
""".trimIndent())
val pgConnection = db.dataSource?.connection?.unwrap(PgConnection::class.java)!!
CopyManager(pgConnection).copyIn(
"COPY temporary_pokemon FROM stdin DELIMITER ',' CSV HEADER",
bufferedReader
)
// snipped - later code INSERTS contents of temporary_pokemon into main pokemon table
}
}
My dependencies in build.gradle.kts:
dependencies {
implementation("org.springframework.boot:spring-boot-starter-jdbc")
implementation("org.jetbrains.kotlin:kotlin-reflect")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8")
implementation("org.postgresql:postgresql")
testImplementation("org.springframework.boot:spring-boot-starter-test")
}
Thanks for any help. I'm not an expert at Spring/JDBC by any means, so apologies in advance if I've missed something that's common knowledge. I've tried searching on SO and Google but to no avail.

Answer 1

Seems like your queries use different connections. So results of first query are not committed when the second query starts. You can get a single connection and use it for execution of both queries or use JdbcTemplate api for importing csv data to your table