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Remove redundant checks from DropSchemaTask #11612

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findepi merged 2 commits into from
Mar 22, 2022
Merged

Remove redundant checks from DropSchemaTask #11612

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2e5b0d1
Remove redundant checks from DropSchemaTask
findepi Mar 22, 2022
ca447e7
Improve Metadata.listTables documentaion
findepi Mar 22, 2022
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16 changes: 2 additions & 14 deletions core/trino-main/src/main/java/io/trino/execution/DropSchemaTask.java
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Original file line number Diff line number Diff line change
Expand Up @@ -92,19 +92,7 @@ private static boolean isSchemaEmpty(Session session, CatalogSchemaName schema,
{
QualifiedTablePrefix tablePrefix = new QualifiedTablePrefix(schema.getCatalogName(), schema.getSchemaName());

// These are best efforts checks that don't provide any guarantees against concurrent DDL operations
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@findinpath findinpath Mar 22, 2022

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It would be beneficial to add views & materialized views in the io.trino.testing.BaseConnectorTest#testDropNonEmptySchema depending on:

  • SUPPORTS_CREATE_VIEW
  • SUPPORTS_CREATE_MATERIALIZED_VIEW

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@findepi findepi Mar 22, 2022

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Good idea, but we would have to test all these 3 cases separately. I don't plan to do this though. Do you want to want to follow up?

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@findinpath findinpath Mar 22, 2022 •
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Yes, I'll create a PR based on your changes.

See #11614

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@findepi findepi Mar 22, 2022

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Yes, I'll create a PR based on your changes.

many thanks!

if (!metadata.listTables(session, tablePrefix).isEmpty()) {
return false;
}

if (!metadata.listViews(session, tablePrefix).isEmpty()) {
return false;
}

if (!metadata.listMaterializedViews(session, tablePrefix).isEmpty()) {
return false;
}

return true;
// This is a best effort check that doesn't provide any guarantees against concurrent DDL operations
return metadata.listTables(session, tablePrefix).isEmpty();
}
}
3 changes: 2 additions & 1 deletion core/trino-main/src/main/java/io/trino/metadata/Metadata.java
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Expand Up @@ -142,7 +142,8 @@ Optional<TableExecuteHandle> getTableHandleForExecute(
TableStatistics getTableStatistics(Session session, TableHandle tableHandle, Constraint constraint);

/**
* Get the names that match the specified table prefix (never null).
* Get the relation names that match the specified table prefix (never null).
* This includes all relations (e.g. tables, views, materialized views).
Comment on lines +145 to +146
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@losipiuk losipiuk Mar 22, 2022

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I did not check. Is this accurate for all the connector now?

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@findinpath findinpath Mar 22, 2022

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I went through all the implementations of io.trino.spi.connector.ConnectorMetadata#listViews and io.trino.spi.connector.ConnectorMetadata#listMaterializedViews and the corresponding listTables implementation does indeed return the views / materialized views as well.

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@findepi findepi Mar 22, 2022

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I did not check. Is this accurate for all the connector now?

even if it wasn't the case yet, we already have this

trino/core/trino-spi/src/main/java/io/trino/spi/connector/ConnectorMetadata.java

Lines 210 to 213 in 8b0c754

/**
* List table, view and materialized view names, possibly filtered by schema. An empty list is returned if none match.
*/
default List<SchemaTableName> listTables(ConnectorSession session, Optional<String> schemaName)

and Metadata just calls that method.

*/
List<QualifiedObjectName> listTables(Session session, QualifiedTablePrefix prefix);

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