Portal does not exists when reading from stream

Hi,

I am using the rxjava implementation (1.3x) and I am facing an error I cannot explain. Scenario : a few million rows in a PgTable.

The following code:

pool.rxGetConnection().flatMapObservable { conn ->
            conn.rxPrepare("SELECT suggestion FROM suggestions WHERE suggestion != keyword AND country = \$1")
                .doOnEach { _ -> println("Prepare on ${Thread.currentThread().getName()}") }
                .flatMapObservable { preparedQuery -> preparedQuery
                    .createStream(10, Tuple.of(country))
                    .toObservable()
                    .doOnCompleted {
                    println("Find suggestions completed on ${Thread.currentThread().getName()}")
                    preparedQuery.close()
                    conn.close()
                }
            }
        }
                                .doOnNext { println("row.getString On ${Thread.currentThread().getName()}") }
                                .map { row -> row.getString("suggestion") }

I get the first 10 results (which makes sense since I have a fetch size of 10 and then I get this error that seems that we are having a cursor issue, somewhere.

io.reactiverse.pgclient.PgException: portal "caeea323-3d74-4af3-bd76-5b3dfb6d7811" does not exist
        at io.reactiverse.pgclient.impl.QueryCommandBase.handleErrorResponse(QueryCommandBase.java:68)
        at io.reactiverse.pgclient.impl.codec.decoder.MessageDecoder.decodeError(MessageDecoder.java:250)
3
        at io.reactiverse.pgclient.impl.codec.decoder.MessageDecoder.decodeMessage(MessageDecoder.java:139)
        at io.reactiverse.pgclient.impl.codec.decoder.MessageDecoder.channelRead(MessageDecoder.java:119)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:340)
        at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1359)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:362)
        at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:348)
        at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:935)
        at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:141)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:645)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:580)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:497)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:459)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:886)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Thread.java:748)

The documentation says that I should be in a Transaction since cursors requires that. I tried to conn.begin() and tx.commit() when I am in doOnCompleted but I end up blocking since the stream doesn’t start.

any idea?

[vietj]

I think that we should prevent creating a cursor when there is no transaction.

For instance the Cursor API could be only available on the transaction API to enforce this.

[kiddouk]

I have been working on isolating why my approach doesn’t work and reading the tests and the javadoc, it is clear that I am at fault here.

In order to benefit from the cursor, I shall create a Transaction. A simple conn.rxQuery("BEGIN").flatMapObservable({ _ -> conn.prepareQuerx.... }) does the trick.

Note that previously, I had done a conn.begin() in order to create a TX but that seems to block the thread and never return anything.

Now that I have something that works, we need to decide if the code shall be patched to create a BEGIN automagically or if we should simply do a doc update.