When H2SchemaMetaDataLoader load column meta data, it will cause NullPointerException

[XinShepherd]

Bug Report

Which version of ShardingSphere did you use?

5.2.1

Which project did you use? ShardingSphere-JDBC or ShardingSphere-Proxy?

ShardingSphere-JDBC

H2 version

      <dependency>
        <groupId>com.h2database</groupId>
        <artifactId>h2</artifactId>
        <version>1.4.200</version>
      </dependency>

Expected behavior

H2 Dialect load table meta data successfully

Actual behavior

Dialect load table meta data error.

the exception is:

2023-02-21 15:25:38.864  INFO 9167 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Starting...
2023-02-21 15:25:38.867  INFO 9167 --- [           main] com.zaxxer.hikari.HikariDataSource       : HikariPool-1 - Start completed.
2023-02-21 15:27:14.538 ERROR 9167 --- [           main] a.s.i.m.d.s.l.SchemaMetaDataLoaderEngine : Dialect load table meta data error.

java.sql.SQLException: Unknown exception: java.lang.NullPointerException
	at org.apache.shardingsphere.infra.util.exception.external.sql.ShardingSphereSQLException.toSQLException(ShardingSphereSQLException.java:54) ~[shardingsphere-infra-util-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.schema.loader.SchemaMetaDataLoaderEngine.loadByDialect(SchemaMetaDataLoaderEngine.java:99) ~[shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.schema.loader.SchemaMetaDataLoaderEngine.load(SchemaMetaDataLoaderEngine.java:65) ~[shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.schema.builder.GenericSchemaBuilder.loadSchemas(GenericSchemaBuilder.java:95) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.schema.builder.GenericSchemaBuilder.build(GenericSchemaBuilder.java:78) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.schema.builder.GenericSchemaBuilder.build(GenericSchemaBuilder.java:66) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabase.create(ShardingSphereDatabase.java:89) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabasesFactory.createGenericDatabases(ShardingSphereDatabasesFactory.java:81) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.infra.metadata.database.ShardingSphereDatabasesFactory.create(ShardingSphereDatabasesFactory.java:69) [shardingsphere-infra-common-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.mode.metadata.MetaDataContextsFactory.create(MetaDataContextsFactory.java:91) [shardingsphere-mode-core-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.mode.metadata.MetaDataContextsFactory.create(MetaDataContextsFactory.java:69) [shardingsphere-mode-core-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.mode.manager.standalone.StandaloneContextManagerBuilder.build(StandaloneContextManagerBuilder.java:49) [shardingsphere-standalone-mode-core-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.driver.jdbc.core.datasource.ShardingSphereDataSource.createContextManager(ShardingSphereDataSource.java:76) [shardingsphere-jdbc-core-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.driver.jdbc.core.datasource.ShardingSphereDataSource.<init>(ShardingSphereDataSource.java:64) [shardingsphere-jdbc-core-5.2.1.jar:5.2.1]
	at org.apache.shardingsphere.driver.api.ShardingSphereDataSourceFactory.createDataSource(ShardingSphereDataSourceFactory.java:93) [shardingsphere-jdbc-core-5.2.1.jar:5.2.1]

Reason analyze (If you can)

I have used the original datasource (not shardingDatasource) to init my tables in H2, and then H2SchemaMetaDataLoader will load the meta data from the datasource.

And then I debug the source code H2SchemaMetaDataLoader.java at line 112 which is the root cause , just like below

From the screenshot，we can find that the dataTypeMap does not contains the dataType '4', because the dataTypeMap is the TYPE_NAME to DATA_TYPE mappings, just like below

Solution

In my option, if we can directly use the value of dataType, and not get from dataTypeMap ?

[strongduanmu]

Hi @XinShepherd, thank you for your feedback. Can you try to fix this bug?

[linghengqian]

From the screenshot，we can find that the dataTypeMap does not contains the dataType '4', because the dataTypeMap is the TYPE_NAME to DATA_TYPE mappings, just like below

• An extra topic is that in the previous H2DataBase mail list, this was pointed out as an error design of H2DataBase V1. Refer to Update H2DataBase to 2.x and drop support for H2Database 1.x #19964 . Because there is no way to test H2Database V1 in the unit test, I am not sure that similar operations are helpful for H2DataBase V1.

[strongduanmu]

@linghengqian Thank you very much for your sharing, which means that the H2 2.x version has corrected the design errors in 1.x, and ShardingSphere currently supports it according to 2.x.

[XinShepherd]

From the screenshot，we can find that the dataTypeMap does not contains the dataType '4', because the dataTypeMap is the TYPE_NAME to DATA_TYPE mappings, just like below

• An extra topic is that in the previous H2DataBase mail list, this was pointed out as an error design of H2DataBase V1. Refer to Update H2DataBase to 2.x and drop support for H2Database 1.x #19964 . Because there is no way to test H2Database V1 in the unit test, I am not sure that similar operations are helpful for H2DataBase V1.

Thanks @linghengqian . So do you mean that I need to upgrade my H2 version from V1 to V2 ? Now shardingsphere-jdbc can work with this error, but I don't know if it will cause other errors.

[linghengqian]

@XinShepherd

• From a maintainability point of view, I feel that a downstream project should not stay at H2Database V1, because according to discussions on the H2Database maillist, V1 will not continue to release new versions.

• You can still make a PR, because I don't know why this method is designed like this in the first place.

[XinShepherd]

• From a maintainability point of view, I feel that a downstream project should not stay at H2Database V1, because according to discussions on the H2Database maillist, V1 will not continue to release new versions.
• You can still make a PR, because I don't know why this method is designed like this in the first place.

Thanks a lot @linghengqian . I upgrade my H2 version now and it works. And also, I will make a PR in the future if necessary.

[linghengqian]

• I'm just updating the current issue to avoid future misunderstandings. org.apache.shardingsphere.infra.metadata.database.schema.loader.dialect.H2SchemaMetaDataLoader has been refactored into org.apache.shardingsphere.infra.database.h2.metadata.data.loader.H2MetaDataLoader. There is still no related PR, and there is almost no way to test H2database V1 Server through H2database V2 Client.

[linghengqian]

Considering the excessive number of CVEs for h2database 1.x, the current issue seems meaningless.