On production I m getting a cryptic stack trace with no indi

Question

On production I m getting a cryptic stack trace with no indication to where this is happening in my code with an ```io r2dbc spi R2dbcBadGrammarException``` it would have been great to have been great if Komapper could try catching such errors and include some info like the sql that was run etc

Toshihiro Nakamura · Answer

Ideally I think the R2DBC driver should include enough information in the R2dbcBadGrammarException However if you could provide a stack trace I would like to consider what can be done with Komapper

dave08 · Answer

```io r2dbc spi R2dbcBadGrammarException You have an error in your SQL syntax check the manual that corresponds to your MySQL server version for the right syntax to use near at line 1 at com github jasync r2dbc mysql JasyncStatement mapException JasyncStatement kt 184 at com github jasync r2dbc mysql JasyncStatement access$mapException JasyncStatement kt 30 at com github jasync r2dbc mysql JasyncStatement$execute$4 invoke JasyncStatement kt 122 at com github jasync r2dbc mysql JasyncStatement$execute$4 invoke JasyncStatement kt 120 at reactor kotlin core publisher FluxExtensionsKt onErrorMap$lambda 1 FluxExtensions kt 172 at reactor core publisher Flux lambda$onErrorMap$28 Flux java 7236 at reactor core publisher Flux lambda$onErrorResume$29 Flux java 7289 at reactor core publisher FluxOnErrorResume$ResumeSubscriber onError FluxOnErrorResume java 94 at reactor core publisher FluxMap$MapSubscriber onError FluxMap java 134 at reactor core publisher FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber maybeOnError FluxConcatMapNoPrefetch java 326 at reactor core publisher FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber innerError FluxConcatMapNoPrefetch java 297 at reactor core publisher FluxConcatMap$ConcatMapInner onError FluxConcatMap java 875 at reactor core publisher MonoCompletionStage$MonoCompletionStageSubscription apply MonoCompletionStage java 122 at reactor core publisher MonoCompletionStage$MonoCompletionStageSubscription apply MonoCompletionStage java 71 at java base java util concurrent CompletableFuture uniHandle Unknown Source at java base java util concurrent CompletableFuture$UniHandle tryFire Unknown Source at java base java util concurrent CompletableFuture postComplete Unknown Source at java base java util concurrent CompletableFuture completeExceptionally Unknown Source at com github jasync sql db util FutureUtilsKt failed FutureUtils kt 18 at com github jasync sql db mysql MySQLConnection$failQueryPromise$1 invoke MySQLConnection kt 418 at com github jasync sql db mysql MySQLConnection$failQueryPromise$1 invoke MySQLConnection kt 417 at com github jasync sql db mysql MySQLConnection failQueryPromise$lambda$13 MySQLConnection kt 417 at java base java util Optional ifPresent Unknown Source at com github jasync sql db mysql MySQLConnection failQueryPromise MySQLConnection kt 417 at com github jasync sql db mysql MySQLConnection setException MySQLConnection kt 218 at com github jasync sql db mysql MySQLConnection onError MySQLConnection kt 212 at com github jasync sql db mysql codec MySQLConnectionHandler channelRead0 MySQLConnectionHandler kt 128 at io netty channel SimpleChannelInboundHandler channelRead SimpleChannelInboundHandler java 99 at io netty channel AbstractChannelHandlerContext invokeChannelRead AbstractChannelHandlerContext java 444 ```

Toshihiro Nakamura · Answer

Thank you for sharing the stack trace of R2dbcBadGrammarException in the DM There was a hint in the stack trace Are you using MySQL 5 and trying to issue a DELETE statement The DELETE statement in MySQL 5 does not support the AS clause

Toshihiro Nakamura · Answer

Komapper supports MySQL version 8 and above

dave08 · Answer

Yes exactly So I guess I ll need to override that too I already have one for upsert

dave08 · Answer

Where did you see the hint

dave08 · Answer

It doesn t show anything about delete

dave08 · Answer

If it doesn t support that AS then the override would be a complete rewrite to avoid the alias a bit more complicated than the upsert

dave08 · Answer

Ooh it seems like this is not in the mysql dialect at all < Toshihiro Nakamura> is there really any way I can override this

dave08 · Answer

Before I wrote that override for upsert I was using `executeScript` and it broke all my unit tests that are mostly running under H2 so overriding the upsert was VERY helpful now if `delete` isn t overridable I m really stuck

Toshihiro Nakamura · Answer

You can override the `getEntityDeleteStatementBuilder` and `getRelationDeleteStatementBuilder` functions in `MySqlR2dbcDialect` Inside the Builder returned from the functions please use `TableNameType NAME ONLY` instead of `TableNameType NAME AND ALIAS`

dave08 · Answer

In both there s ```private val aliasManager = if dialect supportsAliasForDeleteStatement DefaultAliasManager context else EmptyAliasManager ``` maybe it s enough just to override `supportsAliasForDeleteStatement ` < Toshihiro Nakamura>

dave08 · Answer

Or maybe I m not sure what you mean by gt Inside the Builder returned from the functions please use `TableNameType NAME ONLY` instead of `TableNameType NAME AND ALIAS`

dave08 · Answer

So far I d have this in my dialect ``` override fun lt ENTITY Any ID Any META EntityMetamodel lt ENTITY ID META gt gt getEntityDeleteStatementBuilder dialect BuilderDialect context EntityDeleteContext lt ENTITY ID META gt entity ENTITY EntityDeleteStatementBuilder lt ENTITY ID META gt return DefaultEntityDeleteStatementBuilder dialect context entity override fun lt ENTITY Any ID Any META EntityMetamodel lt ENTITY ID META gt gt getRelationDeleteStatementBuilder dialect BuilderDialect context RelationDeleteContext lt ENTITY ID META gt RelationDeleteStatementBuilder lt ENTITY ID META gt return RelationDeleteStatementBuilder dialect context ```

Toshihiro Nakamura · Answer

That s right there is the `supportsAliasForDeleteStatement` function Overriding that function should be sufficient

dave08 · Answer

So basically just adding this to my dialect `override fun supportsAliasForDeleteStatement Boolean = false`

dave08 · Answer

Do you know of any other differences with 5 7 It might avoid me a bunch of surprises Btw so far the way you built Komapper in such a flexible way is really nice ok hand skin tone 3

dave08 · Answer

Just tested that change in production and it works Thanks for the help

dave08 · Answer

Just a little thought I don t think it would be too hard to have the existing Mysql dialect take a parameter in it s constructor `supportFor57` or something these changes aren t too big if they really are the only difference and they might be helpful for others and it s not like providing a whole new dialect for those that still have that obsolete version of mysql it could maybe even be flagged with some kind of experimental or deprecated annotation to indicate that it won t really be supported

dave08 · Answer

Or maybe at least in a FAQ section in the docs to copy and paste for those that need support for 5 7

dave08 · Answer

Also perhaps in the dialects page or other places you should write the minimum versions of the dbs supported so that others won t have this surprise

Toshihiro Nakamura · Answer

We will support MySQL 5 7 in the next release <https github com komapper komapper pull 1108>

dave08 · Answer

Any due date for this release I d really like to use it instead of my implementation there s probably a bunch of things I missed

Toshihiro Nakamura · Answer

We plan to release by November 26 There is a need to write documentation

dave08 · Answer

Oh that s quite a bit of time we need to release this to production in the next few days I guess I ll have to hope for the best that my implementation will do the trick thanks anyways for all this effort