Github user paul-rogers commented on a diff in the pull request:
https://github.com/apache/drill/pull/666#discussion_r91227026
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/rpc/user/UserSession.java ---
@@ -207,25 +239,165 @@ public SchemaPlus getDefaultSchema(SchemaPlus
rootSchema) {
return null;
}
- final SchemaPlus defaultSchema = SchemaUtilites.findSchema(rootSchema,
defaultSchemaPath);
-
- if (defaultSchema == null) {
- // If the current schema resolves to null, return root schema as the
current default schema.
- return defaultSchema;
- }
-
- return defaultSchema;
+ return SchemaUtilites.findSchema(rootSchema, defaultSchemaPath);
}
public boolean setSessionOption(String name, String value) {
return true;
}
+ /**
+ * @return unique session identifier
+ */
+ public String getUuid() { return uuid; }
+
+ /**
+ * Adds temporary table to temporary tables cache.
+ *
+ * @param schema table schema
+ * @param tableName original table name
+ * @return generated temporary table name
+ */
+ public String registerTemporaryTable(AbstractSchema schema, String
tableName) {
+ return temporaryTablesCache.add(schema, tableName);
+ }
+
+ /**
+ * Looks for temporary table in temporary tables cache by its name in
specified schema.
+ *
+ * @param fullSchemaName table full schema name (example, dfs.tmp)
+ * @param tableName original table name
+ * @return temporary table name if found, null otherwise
+ */
+ public String findTemporaryTable(String fullSchemaName, String
tableName) {
+ return temporaryTablesCache.find(fullSchemaName, tableName);
+ }
+
+ /**
+ * Before removing temporary table from temporary tables cache,
+ * checks if table exists physically on disk, if yes, removes it.
+ *
+ * @param fullSchemaName full table schema name (example, dfs.tmp)
+ * @param tableName original table name
+ * @return true if table was physically removed, false otherwise
+ */
+ public boolean removeTemporaryTable(String fullSchemaName, String
tableName) {
+ final AtomicBoolean result = new AtomicBoolean();
+ temporaryTablesCache.remove(fullSchemaName, tableName, new
BiConsumer<AbstractSchema, String>() {
+ @Override
+ public void accept(AbstractSchema schema, String temporaryTableName)
{
+ if (schema.getTable(temporaryTableName) != null) {
+ schema.dropTable(temporaryTableName);
+ result.set(true);
+ }
+ }
+ });
+ return result.get();
+ }
+
private String getProp(String key) {
return properties.get(key) != null ? properties.get(key) : "";
}
private void setProp(String key, String value) {
properties.put(key, value);
}
+
+ /**
+ * Temporary tables cache stores data by full schema name (schema and
workspace separated by dot
+ * (example: dfs.tmp)) as key, and map of generated temporary tables
names
+ * and its schemas represented by {@link AbstractSchema} as values.
+ * Schemas represented by {@link AbstractSchema} are used to drop
temporary tables.
+ * Generated temporary tables consists of original table name and unique
session id.
+ * Cache is represented by {@link ConcurrentMap} so if is thread-safe
and can be used
+ * in multi-threaded environment.
+ *
+ * Temporary tables cache is used to find temporary table by its name
and schema,
+ * to drop all existing temporary tables on session close
+ * or remove temporary table from cache on user demand.
+ */
+ public static class TemporaryTablesCache {
+
+ private final String uuid;
+ private final ConcurrentMap<String, ConcurrentMap<String,
AbstractSchema>> temporaryTables;
+
+ public TemporaryTablesCache(String uuid) {
+ this.uuid = uuid;
+ this.temporaryTables = Maps.newConcurrentMap();
+ }
+
+ /**
+ * Generates temporary table name using its original table name and
unique session identifier.
+ * Caches generated table name and its schema in temporary table cache.
+ *
+ * @param schema table schema
+ * @param tableName original table name
+ * @return generated temporary table name
+ */
+ public String add(AbstractSchema schema, String tableName) {
+ final String temporaryTableName =
SqlHandlerUtil.generateTemporaryTableName(tableName, uuid);
+ final ConcurrentMap<String, AbstractSchema> newValues =
Maps.newConcurrentMap();
+ newValues.put(temporaryTableName, schema);
+ final ConcurrentMap<String, AbstractSchema> oldValues =
temporaryTables.putIfAbsent(schema.getFullSchemaName(), newValues);
+ if (oldValues != null) {
+ oldValues.putAll(newValues);
+ }
+ return temporaryTableName;
+ }
+
+ /**
+ * Looks for temporary table in temporary tables cache.
+ *
+ * @param fullSchemaName table schema name which is used as key in
temporary tables cache
+ * @param tableName original table name
+ * @return generated temporary table name (original name with unique
session id) if table is found,
+ * null otherwise
+ */
+ public String find(String fullSchemaName, String tableName) {
+ final String temporaryTableName =
SqlHandlerUtil.generateTemporaryTableName(tableName, uuid);
+ final ConcurrentMap<String, AbstractSchema> tables =
temporaryTables.get(fullSchemaName);
+ if (tables == null || tables.get(temporaryTableName) == null) {
+ return null;
+ }
+ return temporaryTableName;
+ }
+
+ /**
+ * Removes temporary table from temporary tables cache
+ * by temporary table original name and its schema.
+ *
+ * @param fullSchemaName table schema name which is used as key in
temporary tables cache
+ * @param tableName original table name
+ * @param action action applied to temporary table and its schema
before removing from cache
+ */
+ public void remove(String fullSchemaName, String tableName,
BiConsumer<AbstractSchema, String> action) {
--- End diff --
Oh, clever -- now I see you added a Drill-specific version.
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