SchemaMigrator/SchemaValidator support for Db2

[DavideD]

Follows #536

See #903 for an example with PostgreSQL

Requires a fix from Vert.x SQL Client: eclipse-vertx/vertx-sql-client#1033

See SchemaArrayValidationTestBase

[blafond]

@gbadner When I run the 3 tests for DB2 with GROUPED schema option I get an AIOOB in vertx

Caused by: java.lang.IndexOutOfBoundsException: readerIndex(32741) + length(17) exceeds writerIndex(32757): ReadOnlyByteBuf(ridx: 32741, widx: 32757, cap: 32757/32757, unwrapped: PooledSlicedByteBuf(ridx: 0, widx: 32757, cap: 32757/32757, unwrapped: PooledUnsafeDirectByteBuf(ridx: 32860, widx: 32860, cap: 65536)))
	at io.netty.buffer.AbstractByteBuf.checkReadableBytes0(AbstractByteBuf.java:1442) ~[netty-buffer-4.1.67.Final.jar:4.1.67.Final]
	at io.netty.buffer.AbstractByteBuf.checkReadableBytes(AbstractByteBuf.java:1428) ~[netty-buffer-4.1.67.Final.jar:4.1.67.Final]
	at io.netty.buffer.AbstractByteBuf.skipBytes(AbstractByteBuf.java:971) ~[netty-buffer-4.1.67.Final.jar:4.1.67.Final]
	at io.vertx.db2client.impl.drda.Cursor.skipFdocaBytes(Cursor.java:1669) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.drda.Cursor.calculateColumnOffsetsForRow_(Cursor.java:1488) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.drda.Cursor.stepNext(Cursor.java:220) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.drda.Cursor.next(Cursor.java:232) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.codec.RowResultDecoder.next(RowResultDecoder.java:52) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.codec.ExtendedQueryCommandBaseCodec.decodePreparedQuery(ExtendedQueryCommandBaseCodec.java:81) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.codec.ExtendedQueryCommandCodec.decodeQuery(ExtendedQueryCommandCodec.java:49) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.codec.QueryCommandBaseCodec.decodePayload(QueryCommandBaseCodec.java:69) ~[vertx-db2-client-4.1.3.jar:4.1.3]
	at io.vertx.db2client.impl.codec.DB2Decoder.decodePayload(DB2Decoder.java:79) ~[vertx-db2-client-4.1.3.jar:4.1.3]

[blafond]

Failing on this SQL

select table_name as TABLE_NAME, column_name as COLUMN_NAME,  case when data_type = 'CHARACTER VARYING' then 'VARCHAR' else data_type end as TYPE_NAME, null as COLUMN_SIZE, null as DECIMAL_DIGITS, is_nullable as IS_NULLABLE, null as DATA_TYPE from sysibm.columns where true and table_catalog = ? order by table_catalog, table_schema, table_name, column_name, ordinal_position

[gbadner]

Thanks. @blafond, it's basically the same SQL as is failing for SQL Server.

[gbadner]

I've added a comment about failing on DB2 at eclipse-vertx/vertx-sql-client#1032 (comment) .

[gbadner]

I've been asked to create a separate issue for DB2: eclipse-vertx/vertx-sql-client#1033

[blafond]

@gbadner Pushed my latest: https://github.com/blafond/hibernate-reactive/commits/911-db2-schema-update-validation

[DavideD]

We will also need to update the documentation: ffa7215

[blafond]

Revisiting this... SchemaUpdateDB2TestBase is working with the internal individual schema class, but tests fail with GroupedSchemaUpdateDB2TestBase class

[blafond]

No movement on DB2 vertx client, so tests still failing.