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https://issues.apache.org/jira/browse/DERBY-2946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12523074
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Knut Anders Hatlen commented on DERBY-2946:
-------------------------------------------
Just a thought...
In GenericLanguageConnectionContext, there is a method which looks like this:
public PreparedStatement prepareInternalStatement(SchemaDescriptor
compilationSchema, String sqlText, boolean isForReadOnly, boolean forMetaData)
throws StandardException
{
return connFactory.getStatement(compilationSchema, sqlText,
isForReadOnly).prepare(this, forMetaData);
}
Would it work if we added something like
if (forMetaData) compilationSchema = systemSchema;
to this method?
> In soft upgrade mode, the metadata queries do not get compiled in SYS schema.
> This will cause problems in future releases of Derby.
> -----------------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-2946
> URL: https://issues.apache.org/jira/browse/DERBY-2946
> Project: Derby
> Issue Type: Bug
> Components: SQL
> Affects Versions: 10.4.0.0
> Reporter: Mamta A. Satoor
>
> EmbedDatabaseMetaData implements metadata queries. The implementation of
> metadata queries in EmbedDatabaseMetaData checks if we are in soft upgrade
> mode (getPreparedQuery() has following code)
> if (notInSoftUpgradeMode())
> s = getPreparedQueryUsingSystemTables(queryName, net);
> else {
> try {
> //Can't use stored prepared statements because we are in soft
> upgrade
> //mode and hence need to get metadata sql from
> metadata.properties file
> //or metadata_net.properties
> String queryText = getQueryFromDescription(queryName, net);
> s = getEmbedConnection().prepareMetaDataStatement(queryText);
> } catch (Throwable t) {
> throw handleException(t);
> }
> }
> So, when running in soft upgrade mode, we do not go through SYSSTATEMENT but
> this will cause the metadata query to run in whatever the current schema may
> be rather than in SYS schema. This is not a problem in Derby 10.3 release
> because during soft upgarde, the collation will always be UCS_BASIC and hence
> collation mismatch can't happen.
> But in Derby 10.3, a user can create a database with territory based
> collation. When such a database will be in soft upgrade mode for say Derby
> 10.4, the metadata queries will run into problem if they are run in a user
> schema. This is because in soft upgrade mode, we do not go through
> SYSSTATEMENTS and instead compile the metadata queries in current schema. If
> the current schema is user schema, then character string literals in metadata
> queries will get the collation type of territory based and when compared with
> character string colunms from SYS tables with collation type of UCS_BASIC, we
> will end up getting compilation error for the metadata queries. So, before
> the next release, we will have to fix this problem. One solution may be to
> somehow make the current compilation schema as SYS when running the metadata
> queries in soft upgrade mode.
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