Roberto,
does it also happen with other DDL / ALTER statements,
or only with
ALTER TABLE qname SET { { READ | INSERT } ONLY | READ WRITE }
as the error message suggests?
Thanks!
Stefan
----- On Aug 1, 2018, at 10:25 AM, Roberto Cornacchia roberto.cornacchia@gmail.com wrote:
> Thanks Stefan.
> Then I guess we'll loop until it succeeds.
>
> What is annoying is that this could in principle happen at every statement
> executed, so in principle all statements should be wrapped with this loop.
>
>
>
> On Tue, 31 Jul 2018 at 18:03 Stefan Manegold < Stefan.Manegold@cwi.nl > wrote:
>
>
> Hi,
>
> just a "wild" guess: WAL (write ahead log) not flushed, yet?
> IMHO there is no (easy) way to check that (outside the MonetDB kernel)
>
> Stefan
>
> ----- On Jul 31, 2018, at 5:43 PM, Roberto Cornacchia
> roberto.cornacchia@gmail.com wrote:
>
>> Hi,
>>
>> We are having a problem, for a while, that is difficult to isolate.
>>
>> Our ETL includes the following steps:
>>
>> 1) Open JDBC connection, add data to a table, commit, close connection
>> 2) Open JDBC connection, some ALTER TALBLE statements, commit, close connection
>>
>> Occasionally, we get the following during step 2) :
>>
>> java.sql.SQLException: ALTER TABLE: set READ or INSERT ONLY not possible with
>> outstanding updates (wait until updates are flushed)
>> at
>> nl.cwi.monetdb.jdbc.MonetConnection$ResponseList.executeQuery(MonetConnection.java:2732)
>>
>> What puzzles me is that step one is completed when this happens, the commit is
>> done and the connection is closed (we triple-checked that is actually is
>> closed).
>>
>> Notice that inserting a sleep between the to steps makes it work correctly.
>>
>> As I said, this is hard to isolate and reproduce. Still, can anyone guess what
>> is exactly happening?
>> Can it be that a background process is still flushing updates from step 1) ?
>> Even if the JDBC connection is closed ?
>> Can we force a blocking flush, so that it doesn't return until it's safe?
>> If not, how can we know when updates are flushed?
>>
>> Thanks, Roberto
>>
>>
>>
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>
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