HSQLDB：我正在尝试使用临时表中的一些数据填充表，但数据正在被删除

I'm using HSQLDB. Inside a java function I'm creating a temporary table and populating it with some data. Right after I'm updating a regular table with the data from the temporary table.

我正在使用HSQLDB。在java函数中，我正在创建一个临时表并用一些数据填充它。在我用临时表中的数据更新常规表之后。

If I debug the code inside the function and perform SELECT I can see that the data was indeed updated in both tables, but after committing the changes the table is no longer updated! (the regular table, not the temporary one).

如果我调试函数内部的代码并执行SELECT，我可以看到两个表中的数据确实已更新，但在提交更改后，表不再更新！（常规表，而不是临时表）。

When I created the temp table I used: ON COMMIT PRESERVE ROWS but it doesn't help.

当我创建我使用的临时表时：ON COMMIT PRESERVE ROWS但它没有帮助。

Does anyone know why is this happening?

有谁知道为什么会这样？

Thanks!

谢谢！

Here is the code:

这是代码：

public synchronized void foo(String[] objectsToMark) throws Exception {

        String createTempTableQuery = "CREATE TEMP TABLE "+TEMP_TABLE_NAME+"(OBJECTID VARCHAR) " +
                "ON COMMIT PRESERVE ROWS";
        String dropTempTableQuery = "DROP TABLE "+TEMP_TABLE_NAME;

        String updateQueryString = "update " + TABlE_A + " set " +TABlE_A+".X = 'N' where "+TABlE_A+".RESULT_ID in (select "+TABlE_A+".RESULT_ID FROM "+TABlE_A
                        +" inner join "+TABLE_B+" on "+TABLE_B+".OBJECTID = "+TABlE_A+".OBJECTID"
                        +" inner join TEMP_TABLE on "+TABLE_B+".OBJECTID = TEMP_TABLE.OBJECTID"
                        +" where "+TABlE_A+".IS_X = 'Y')";

        String insertObjectIDs = "INSERT INTO " + TEMP_TABLE_NAME + " (OBJECTID) VALUES (?)";
        Connection conn = null;
        Statement stmt = null;
        PreparedStatement psInsertObjectIDs = null;
        try {
            conn = getConnection(getClass().getName() + "");
            stmt = conn.createStatement();


            stmt.execute(createTempTableQuery);

            // insert object's IDs into table
            psInsertObjectIDs = conn.prepareStatement(insertObjectIDs);

            for (String id : objectsToMark) {
                int i = 0;
                psInsertObjectIDs.setString(++i, id);
                psInsertObjectIDs.addBatch();
            }
            psInsertObjectIDs.executeBatch();

            stmt.execute(updateQueryString);

        } catch (Exception e) {
        } finally {
            // close resources
            close(stmt);
            stmt = null;
            // drop the temporary tables
            if (conn != null) {
                try {
                    stmt = conn.createStatement();
                    stmt.execute(dropTempTableQuery);
                } catch (SQLException e) {
                }
                close(stmt);
            }

            close(psInsertObjectIDs);
            closeConnection(conn);
        }
    }

Notice that there is no commit here but the connection is configured to perform auto commit.

请注意，此处没有提交，但连接已配置为执行自动提交。

1 个解决方案

#1

As the code works when you debug, the problem must be outside this code.

由于代码在您调试时有效，因此问题必须在此代码之外。

If you are running this code as an isolated test on a file: database, and you have not specified a write delay or shutdown option in the jdbc connection url, then the engine does not get enough time to write the data to disk.

如果您将此代码作为文件：数据库的隔离测试运行，并且您没有在jdbc连接URL中指定写入延迟或关闭选项，则引擎没有足够的时间将数据写入磁盘。

The default settings of HSQLDB are for production, where a SHUTDOWN is issued by the application program. For tests, use either of the properties below.

HSQLDB的默认设置用于生产，其中SHUTDOWN由应用程序发出。对于测试，请使用以下任一属性。

This one writes the changes after each commit or auto-commit, therefore slows down production databases:

这个在每次提交或自动提交后写入更改，因此减慢了生产数据库的速度：

jdbc:hsqldb:file:mydb;hsqldb.write_delay=false

This one shuts down the database when the only remaining connection is closed:

当唯一剩余的连接关闭时，这个关闭数据库：

jdbc:hsqldb:file:mydb;shutdown=true

As this issue comes up quite often, future versions of HSQLDB from 2.2.9 will always write the data to disk when the only remaining connection is closed.

由于此问题经常出现，因此2.2.9的HSQLDB的未来版本将始终在剩余的唯一连接关闭时将数据写入磁盘。

#1