[ https://issues.apache.org/jira/browse/ARROW-10492?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
ASF GitHub Bot updated ARROW-10492: ----------------------------------- Labels: pull-request-available (was: ) > [Java][JDBC] Allow users to config the mapping between SQL types and Arrow > types > -------------------------------------------------------------------------------- > > Key: ARROW-10492 > URL: https://issues.apache.org/jira/browse/ARROW-10492 > Project: Apache Arrow > Issue Type: Improvement > Components: Java > Reporter: Liya Fan > Assignee: Liya Fan > Priority: Major > Labels: pull-request-available > Time Spent: 10m > Remaining Estimate: 0h > > According to the current implementation of JDBC adapter, the conversion > between SQL types and Arrow types is hard-coded. This will cause some > problems in practice: > # The appropriate conversion may vary for different databases. For example, > for SQL Server, type {{real}} corresponds to 4 byte floating point values > ([https://docs.microsoft.com/en-us/sql/t-sql/data-types/float-and-real-transact-sql?view=sql-server-ver15),] > whereas for SQLite, \{{real}} corresponds to 8 byte floating point values > ([https://www.sqlitetutorial.net/sqlite-data-types/).] If the maping is not > right, some extra conversion would happen, which can impact performance > severely. > # Our current implementation determines the type conversion solely based on > the type ID. However, the appropriate conversion may also depend some other > information, like precision and scale. For example, for {{FLOAT( n )}}, it > should correspond to 4 byte floating point values, if n <= 24, otherwise, it > should correspond to 8 byte floating point values. > To address the problems, we should allow users to customize the conversion > between SQL and Arrow types. -- This message was sent by Atlassian Jira (v8.3.4#803005)