PgArray does not implement Serializable Interface

[MahatmaFatalError]

Is there a reason why PgArray does not implement Serializable Interface?

Would be beneficial for some ORM caching mechanisms like MyBatis which relies on serializable objects

[davecramer]

Likely because it is not required in the spec. Feel free to provide us with a Pull Request

[vlsi]

@MahatmaFatalError , can you please clarify which MyBatis scenario relies serializable?

[MahatmaFatalError]

@vlsi please take a look at http://www.mybatis.org/mybatis-3/sqlmap-xml.html#cache as it states "A read-write cache will return a copy (via serialization) of the cached object." Thus, MyBatis caching must be disabled in order to avoid
org.apache.ibatis.cache.CacheException: Error serializing object. Cause: java.io.NotSerializableException when querying for a ResultSet containing an sql.Array.

@davecramer ok, I'will give it a try soon

[vlsi]

Here's a quote from the spec

https://docs.oracle.com/javase/7/docs/api/java/sql/Array.html
By default, an Array value is a transaction-duration reference to an SQL ARRAY value. By default, an Array object is implemented using an SQL LOCATOR(array) internally, which means that an Array object contains a logical pointer to the data in the SQL ARRAY value rather than containing the ARRAY value's data

That means, the whole serializable concept of mybatis is flawed -- it should not try to access Array object outside of transaction.

I'm not sure if pgjdbc would be always to keep arrays serializable, so I'm inclined to decline the proposal.

[MahatmaFatalError]

OK, to avoid this issue I could go by casting the Array to String within the query via array_to_string function and let the caller handle the ResultSet accordingly in order to leverage MyBatis caching capabilities (for Strings).

Just for interest, what would be a good caching mechanism on ORM side for sql.Array

[vlsi]

Just for interest, what would be a good caching mechanism on ORM side for sql.Array

It could be like: fetch all the contents, create own implementation of sql.Array, hunt bugs when user tries to use cached array instance in statement.setArray

[MahatmaFatalError]

Final just for interest question ;)

would https://docs.oracle.com/javase/7/docs/api/javax/sql/rowset/serial/SerialArray.html help in this situation in any way?

[vlsi]

Ah, rowset indeed could help here.