Refactor JDBCSource to add compile-time info about type of DB #1087
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- Turn drivers into traits - Put all driver-specific logic in those traits
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Bump. I think it seems I'm getting more support for this approach rather than the run-time approach. Could someone review this? Also let me know what you think about all the implicits using DriverColumnDefiner. Arguably we should just put convenience methods like |
| case class ColumnDefinition(name: ColumnName, definition: Definition) | ||
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| trait ColumnDefiner { | ||
| val columns: Iterable[ColumnDefinition] |
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Can we use def here to lesson the chance of a val init order null?
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This looks good to me. Just a couple of comments. Since I'm OOO, I'd like if someone at Twitter would click merge. |
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looks good to me. @ianoc merge? |
ianoc
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Nov 10, 2014
Refactor JDBCSource to add compile-time info about type of DB
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This builds off @jcoveney's PR #1010. I figured I'd leave his branch alone, since this takes a slightly different approach.
Since we've pushed the type of DB for a source to compile time, opted to turn drivers into traits. Put all driver-specific logic there. (not only generating the correct SQL for table creation, but also things like getting the correct JDBCSchema).
JDBCSourceCompileTestis an example source that exercises this code. IMO this is less boilerplate than having the driver as a generic type.I've also pulled out components of JDBCSource to its own file, since the one file was getting pretty gigantic.
[WIP] still need to do Vertica. Just thought I would get it out there for some comments.
Also had some offline discussions with @ianoc. This change requires that we change existing all JDBCSources, which is a lot of friction. Another possibility is to push SQL generation to run-time, after picking up the correct driver (currently the SQL to create the table is basically generated at compile time). This has the trade-off that
(positive) is a smaller change in API and allows us to swap databases
(negative) if a DB does not support a specific column or other such issues (mentioned by @jcoveney as an advantage to this approach in #1010) only manifest at run time.