MySQL Cookbook

Getting LOAD DATA to Cough Up More Information

Problem

LOAD DATA doesn’t tell you much about problems in the datafile.

Solution

There is no solution. Well, maybe there is.

Discussion

When a LOAD DATA statement finishes, it returns a line of information that tells you how many errors or data conversion problems occurred. Suppose you load a file into a table and see the following message when LOAD DATA finishes.

Records: 134  Deleted: 0  Skipped: 2  Warnings: 13

These values provide some general information about the import operation:

• Records indicates the number of records found in the file.

• Deleted and Skipped are related to treatment of input records that duplicate existing table records on unique index values. Deleted indicates how many records were deleted from the table and replaced by input records, and Skipped indicates how many input records were ignored in favor of existing records.

• Warnings is something of a catch-all that indicates the number of problems found while loading data values into columns. Either a value stores into a column properly, or it doesn’t. In the latter case, the value ends up in MySQL as something different and MySQL counts it as a warning. (Storing a string abc into a numeric column results in a stored value of 0, for example.)

What do these values tell you? The Records value normally should match the number of lines in the input file. If it is different than the file’s line count, that’s a sign that MySQL is interpreting the file as having a format that ...