You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@beam.apache.org by "Sivanand (JIRA)" <ji...@apache.org> on 2018/05/18 04:13:00 UTC
[jira] [Created] (BEAM-4359) String encoding for a spanner mutation
assumes that string length equals bytes length
Sivanand created BEAM-4359:
------------------------------
Summary: String encoding for a spanner mutation assumes that string length equals bytes length
Key: BEAM-4359
URL: https://issues.apache.org/jira/browse/BEAM-4359
Project: Beam
Issue Type: Bug
Components: io-java-gcp
Affects Versions: 2.4.0
Reporter: Sivanand
Assignee: Chamikara Jayalath
The bug is here:
https://github.com/apache/beam/blob/3ba96003d31ce98a54c0c51c1c0a9cf7c06e2fa2/sdks/java/io/google-cloud-platform/src/main/java/org/apache/beam/sdk/io/gcp/spanner/MutationGroupEncoder.java#L231-L235
{code}
case STRING: {
String str = value.getString();
VarInt.encode(str.length(), bos);
bos.write(str.getBytes(StandardCharsets.UTF_8));
break;
}
{code}
The code assumes that the number of bytes used to represent a UTF_8 String equals the string length. This is not true because a UTF_8 character can be encoded using 1 - 4 bytes.
From wikipedia: https://en.wikipedia.org/wiki/UTF-8
{quote}UTF-8 is a variable width character encoding capable of encoding all 1,112,064 valid code points in Unicode using one to four 8-bit bytes{quote}
Code to recreate the issue:
{code}
/*
Schema in spanner
CREATE TABLE test (
id INT64,
testString STRING(MAX),
number INT64,
) PRIMARY KEY (id)
*/
import com.google.cloud.spanner.Mutation;
import com.google.common.collect.Lists;
import org.apache.beam.runners.direct.DirectRunner;
import org.apache.beam.sdk.io.gcp.spanner.SpannerIO;
import org.apache.beam.sdk.testing.TestPipeline;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.ParDo;
import org.junit.Rule;
import org.junit.Test;
import java.io.Serializable;
import java.util.List;
public class BeamSpannerTest implements Serializable {
@Rule
public transient TestPipeline pipeline = TestPipeline.create();
@Test
public void testSpanner() {
pipeline.getOptions().setRunner(DirectRunner.class);
List<String> strdata = Lists.newArrayList("၃7");
pipeline.apply(
Create.of(strdata)
).apply(ParDo.of(new DoFn<String, Mutation>() {
@ProcessElement
public void processElement(ProcessContext c) {
String value = c.element();
c.output(Mutation.newInsertOrUpdateBuilder("test")
.set("id").to(1)
.set("testString").to(value)
.set("number").to(10)
.build());
}
})
).apply("Write to Spanner", SpannerIO.write()
.withProjectId("my-project")
.withInstanceId("spanner-instance")
.withDatabaseId("test")
);
pipeline.run();
}
}
{code}
After running the code, the value in the column {{number}} will be {{7043}} and not {{10}} because the bytes from the previous column {{testString}} have spilled into the {{number}}
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)