[jira] [Resolved] (IMPALA-10468) DROP events which are generated while a batch is being processed may add table incorrectly

["Vihang Karajgaonkar (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/IMPALA-10468?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Vihang Karajgaonkar resolved IMPALA-10468.
------------------------------------------
    Fix Version/s: Impala 4.1
       Resolution: Duplicate

> DROP events which are generated while a batch is being processed may add table incorrectly
> ------------------------------------------------------------------------------------------
>
>                 Key: IMPALA-10468
>                 URL: https://issues.apache.org/jira/browse/IMPALA-10468
>             Project: IMPALA
>          Issue Type: Bug
>            Reporter: Vihang Karajgaonkar
>            Assignee: Vihang Karajgaonkar
>            Priority: Major
>             Fix For: Impala 4.1
>
>
> One of the problems with CREATE/DROP events is that they may occur while a batch is being processed and hence EventsProcessor may not able aware of that.
> For example, consider the following sequence of statements:
> create table foo (c1 int);
> drop table foo;
> create table foo (c2 int);
> drop table foo;
> These statements will generate CREATE_TABLE, DROP_TABLE,  CREATE_TABLE, DROP_TABLE event sequence. Generally, if all these 4 events are fetched in a batch, then the first CREATE_TABLE and third CREATE_TABLE is ignored because it is followed by the a DROP_TABLE in the sequence and the DROP_TABLE events take no effect since the table doesn't exist in catalogd anymore.
> However, if the events processor fetches these events in 2 batches (3 and 1) then after the first batch of CREATE_TABLE, DROP_TABLE,  CREATE_TABLE is processed, the third event will add the table foo in the catalogd. The subsequent batch's DROP_TABLE will be processed and remove the table, but between the two batches, catalogd will say that a table called foo exists. This can lead to statements getting errored out. Eg. a statement like create table foo (c3 int) after the above statements will error out with a TableAlreadyExists error.
> The problem happens for databases too. So far I have not been able to reproduce this for Partitions but I don't see why it will not happen with Partitions also.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: issues-all-unsubscribe@impala.apache.org
For additional commands, e-mail: issues-all-help@impala.apache.org