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Posted to dev@ignite.apache.org by Vladimir Steshin <vl...@gmail.com> on 2020/01/29 08:16:40 UTC
Question: Table scheme 'default'
Hi ppl. Wanted to ask is issue a bug. Minor propably.
Recently noticed that one simple query returns a value which can't be found
'as is' in following query. I tried to find and drop all the tables I
created with "create table":
select schema_name, table_name, cache_name from sys.tables
And there are tables which were not created with 'create table...'. For
example, table 'default.Person' from the test/tutorial I was researching.
Ok. I tried to delete them too. Now I know this is prohibited. But why I
got error: scheme 'default' not found? I just received this schema name
from previous query.
To avoid this I had to capitalize schema name taking it into "":
"default".Person. Then I got normal error like 'only cache created tables
can be removed with drop table.'.
One select returns value which can't be found in second select
(delete/drop). Isn't it a bug from SQL's point of view?
Re: Question: Table scheme 'default'
Posted by Ivan Pavlukhin <vo...@gmail.com>.
> I think this case should fail with error like "only cache created tables
> can be removed with drop table. ", not with "scheme not found."
> SQL-engine is supposed to accept and understand values it returns itself.
Agree. Feel free to contribute a fix. My expectation here is that it
will not be a trivial one.
пт, 31 янв. 2020 г. в 18:22, Vladimir Steshin <vl...@gmail.com>:
>
> //Got a connectionConnection conn = ...;
>
> //execute() - is just a helper function. Creates prepared statement, pass
> params...
> //Get all the tables
> List<List<?>> lst = execute(conn, "select SCHEMA_NAME, TABLE_NAME from
> SYS.TABLES");
>
> for( List<?> row : lst ){
> String schemaName = (String)row.get(0);
> String tableName = (String)row.get(1);
>
> //Shows: "schema: default, table: PERSON"
> System.out.println("schema: " + schemName + ", table: " +
> tableName));
>
> //Fails with with: java.sql.SQLException: Failed to parse query.
> Схема "DEFAULT" не найдена
> execute( conn, "drop table "+schemaName + "."+tableName+"'" );
> }
>
> I think this case should fail with error like "only cache created tables
> can be removed with drop table. ", not with "scheme not found."
> SQL-engine is supposed to accept and understand values it returns itself.
>
>
> пт, 31 янв. 2020 г. в 11:29, Ivan Pavlukhin <vo...@gmail.com>:
>
> > Vladimir,
> >
> > I will try to shed a light on this.
> > 1. Statically configured tables in caches (QueryEntity) by default
> > resides in a schema having the same name as a cache it belongs to
> > ("default" is a cache and a schema name for a table Person in your
> > example).
> > 2. As you might know SQL literals are case-insensitive if they used
> > without quotes. And Ignite SQL uses a quite naive approach for a
> > case-insensitive comparison. It simply converts all case-insensitive
> > names to upper case and compares after that.
> > 3. And we observe consequences of such naive comparison. A schema name
> > (equal to a cache name) is treated case-sensitive and saved as is
> > ("default" in lower case). Query "SELECT ... FROM default.Person"
> > passes schema name as case-insensitive. Ignite converts a schema from
> > the query to upper case "DEFAULT" and searches for a schema with that
> > name (using ordinary case-sensitive string comparison). But as there
> > is only "default" in lower case it fails to find a schema.
> >
> > So, it is a bug. But for me personally it looks like the bug causes a
> > not major usability problem.
> >
> > ср, 29 янв. 2020 г. в 12:27, Nikolay Izhikov <ni...@apache.org>:
> > >
> > > Vladimir.
> > >
> > > Please, provide a simple, self-contained reproducer to the issue you
> > described.
> > >
> > > > 29 янв. 2020 г., в 11:16, Vladimir Steshin <vl...@gmail.com>
> > написал(а):
> > > >
> > > > Hi ppl. Wanted to ask is issue a bug. Minor propably.
> > > >
> > > > Recently noticed that one simple query returns a value which can't be
> > found
> > > > 'as is' in following query. I tried to find and drop all the tables I
> > > > created with "create table":
> > > >
> > > > select schema_name, table_name, cache_name from sys.tables
> > > >
> > > > And there are tables which were not created with 'create table...'. For
> > > > example, table 'default.Person' from the test/tutorial I was
> > researching.
> > > > Ok. I tried to delete them too. Now I know this is prohibited. But why
> > I
> > > > got error: scheme 'default' not found? I just received this schema name
> > > > from previous query.
> > > >
> > > > To avoid this I had to capitalize schema name taking it into "":
> > > > "default".Person. Then I got normal error like 'only cache created
> > tables
> > > > can be removed with drop table.'.
> > > >
> > > > One select returns value which can't be found in second select
> > > > (delete/drop). Isn't it a bug from SQL's point of view?
> > >
> >
> >
> > --
> > Best regards,
> > Ivan Pavlukhin
> >
--
Best regards,
Ivan Pavlukhin
Re: Question: Table scheme 'default'
Posted by Vladimir Steshin <vl...@gmail.com>.
//Got a connectionConnection conn = ...;
//execute() - is just a helper function. Creates prepared statement, pass
params...
//Get all the tables
List<List<?>> lst = execute(conn, "select SCHEMA_NAME, TABLE_NAME from
SYS.TABLES");
for( List<?> row : lst ){
String schemaName = (String)row.get(0);
String tableName = (String)row.get(1);
//Shows: "schema: default, table: PERSON"
System.out.println("schema: " + schemName + ", table: " +
tableName));
//Fails with with: java.sql.SQLException: Failed to parse query.
Схема "DEFAULT" не найдена
execute( conn, "drop table "+schemaName + "."+tableName+"'" );
}
I think this case should fail with error like "only cache created tables
can be removed with drop table. ", not with "scheme not found."
SQL-engine is supposed to accept and understand values it returns itself.
пт, 31 янв. 2020 г. в 11:29, Ivan Pavlukhin <vo...@gmail.com>:
> Vladimir,
>
> I will try to shed a light on this.
> 1. Statically configured tables in caches (QueryEntity) by default
> resides in a schema having the same name as a cache it belongs to
> ("default" is a cache and a schema name for a table Person in your
> example).
> 2. As you might know SQL literals are case-insensitive if they used
> without quotes. And Ignite SQL uses a quite naive approach for a
> case-insensitive comparison. It simply converts all case-insensitive
> names to upper case and compares after that.
> 3. And we observe consequences of such naive comparison. A schema name
> (equal to a cache name) is treated case-sensitive and saved as is
> ("default" in lower case). Query "SELECT ... FROM default.Person"
> passes schema name as case-insensitive. Ignite converts a schema from
> the query to upper case "DEFAULT" and searches for a schema with that
> name (using ordinary case-sensitive string comparison). But as there
> is only "default" in lower case it fails to find a schema.
>
> So, it is a bug. But for me personally it looks like the bug causes a
> not major usability problem.
>
> ср, 29 янв. 2020 г. в 12:27, Nikolay Izhikov <ni...@apache.org>:
> >
> > Vladimir.
> >
> > Please, provide a simple, self-contained reproducer to the issue you
> described.
> >
> > > 29 янв. 2020 г., в 11:16, Vladimir Steshin <vl...@gmail.com>
> написал(а):
> > >
> > > Hi ppl. Wanted to ask is issue a bug. Minor propably.
> > >
> > > Recently noticed that one simple query returns a value which can't be
> found
> > > 'as is' in following query. I tried to find and drop all the tables I
> > > created with "create table":
> > >
> > > select schema_name, table_name, cache_name from sys.tables
> > >
> > > And there are tables which were not created with 'create table...'. For
> > > example, table 'default.Person' from the test/tutorial I was
> researching.
> > > Ok. I tried to delete them too. Now I know this is prohibited. But why
> I
> > > got error: scheme 'default' not found? I just received this schema name
> > > from previous query.
> > >
> > > To avoid this I had to capitalize schema name taking it into "":
> > > "default".Person. Then I got normal error like 'only cache created
> tables
> > > can be removed with drop table.'.
> > >
> > > One select returns value which can't be found in second select
> > > (delete/drop). Isn't it a bug from SQL's point of view?
> >
>
>
> --
> Best regards,
> Ivan Pavlukhin
>
Re: Question: Table scheme 'default'
Posted by Ivan Pavlukhin <vo...@gmail.com>.
Vladimir,
I will try to shed a light on this.
1. Statically configured tables in caches (QueryEntity) by default
resides in a schema having the same name as a cache it belongs to
("default" is a cache and a schema name for a table Person in your
example).
2. As you might know SQL literals are case-insensitive if they used
without quotes. And Ignite SQL uses a quite naive approach for a
case-insensitive comparison. It simply converts all case-insensitive
names to upper case and compares after that.
3. And we observe consequences of such naive comparison. A schema name
(equal to a cache name) is treated case-sensitive and saved as is
("default" in lower case). Query "SELECT ... FROM default.Person"
passes schema name as case-insensitive. Ignite converts a schema from
the query to upper case "DEFAULT" and searches for a schema with that
name (using ordinary case-sensitive string comparison). But as there
is only "default" in lower case it fails to find a schema.
So, it is a bug. But for me personally it looks like the bug causes a
not major usability problem.
ср, 29 янв. 2020 г. в 12:27, Nikolay Izhikov <ni...@apache.org>:
>
> Vladimir.
>
> Please, provide a simple, self-contained reproducer to the issue you described.
>
> > 29 янв. 2020 г., в 11:16, Vladimir Steshin <vl...@gmail.com> написал(а):
> >
> > Hi ppl. Wanted to ask is issue a bug. Minor propably.
> >
> > Recently noticed that one simple query returns a value which can't be found
> > 'as is' in following query. I tried to find and drop all the tables I
> > created with "create table":
> >
> > select schema_name, table_name, cache_name from sys.tables
> >
> > And there are tables which were not created with 'create table...'. For
> > example, table 'default.Person' from the test/tutorial I was researching.
> > Ok. I tried to delete them too. Now I know this is prohibited. But why I
> > got error: scheme 'default' not found? I just received this schema name
> > from previous query.
> >
> > To avoid this I had to capitalize schema name taking it into "":
> > "default".Person. Then I got normal error like 'only cache created tables
> > can be removed with drop table.'.
> >
> > One select returns value which can't be found in second select
> > (delete/drop). Isn't it a bug from SQL's point of view?
>
--
Best regards,
Ivan Pavlukhin
Re: Question: Table scheme 'default'
Posted by Nikolay Izhikov <ni...@apache.org>.
Vladimir.
Please, provide a simple, self-contained reproducer to the issue you described.
> 29 янв. 2020 г., в 11:16, Vladimir Steshin <vl...@gmail.com> написал(а):
>
> Hi ppl. Wanted to ask is issue a bug. Minor propably.
>
> Recently noticed that one simple query returns a value which can't be found
> 'as is' in following query. I tried to find and drop all the tables I
> created with "create table":
>
> select schema_name, table_name, cache_name from sys.tables
>
> And there are tables which were not created with 'create table...'. For
> example, table 'default.Person' from the test/tutorial I was researching.
> Ok. I tried to delete them too. Now I know this is prohibited. But why I
> got error: scheme 'default' not found? I just received this schema name
> from previous query.
>
> To avoid this I had to capitalize schema name taking it into "":
> "default".Person. Then I got normal error like 'only cache created tables
> can be removed with drop table.'.
>
> One select returns value which can't be found in second select
> (delete/drop). Isn't it a bug from SQL's point of view?