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PHOENIX-7748 Empty column cell is not returned when scan has both EmptyColumnOnlyFilter and DistinctPrefixFilter #2353

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Merged
tkhurana merged 3 commits into from
Jan 27, 2026
+116 −1
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PHOENIX-7748 Empty column cell is not returned when scan has both EmptyColumnOnlyFilter and DistinctPrefixFilter #2353

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98b300b
PHOENIX-7748 Empty column cell is not returned when scan has both Emp…
Jan 21, 2026
a4f30f0
Address review comments
Jan 26, 2026
a2cd2b5
Fix spotless warnings
Jan 27, 2026
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19 changes: 18 additions & 1 deletion phoenix-core-client/src/main/java/org/apache/phoenix/filter/EmptyColumnOnlyFilter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,7 @@ public class EmptyColumnOnlyFilter extends FilterBase implements Writable {
private byte[] emptyCQ;
private boolean found = false;
private boolean first = true;
private Cell emptyColumnCell = null;

public EmptyColumnOnlyFilter() {
}
Expand All @@ -54,6 +55,7 @@ public EmptyColumnOnlyFilter(byte[] emptyCF, byte[] emptyCQ) {
public void reset() throws IOException {
found = false;
first = true;
emptyColumnCell = null;
}

// No @Override for HBase 3 compatibility
Expand All @@ -68,6 +70,7 @@ public ReturnCode filterCell(final Cell cell) throws IOException {
}
if (ScanUtil.isEmptyColumn(cell, emptyCF, emptyCQ)) {
found = true;
emptyColumnCell = cell;
return ReturnCode.INCLUDE;
}
if (first) {
Expand All @@ -79,8 +82,22 @@ public ReturnCode filterCell(final Cell cell) throws IOException {

@Override
public void filterRowCells(List<Cell> kvs) throws IOException {
if (kvs.size() > 1) {
if (kvs.size() > 2) {
throw new IOException("EmptyColumnOnlyFilter got unexpected cells: " + kvs.size());
} else if (kvs.size() == 2) {
// remove the first cell and only return the empty column cell
kvs.remove(0);
} else if (kvs.size() == 1) {
// we only have 1 cell, check if it is the empty column cell or not
// since the empty column cell could have been excluded by another filter like the
// DistinctPrefixFilter.
Cell cell = kvs.get(0);
if (found && !ScanUtil.isEmptyColumn(cell, emptyCF, emptyCQ)) {
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@kadirozde kadirozde Jan 23, 2026

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Does this really happen in ITs or is it just a defensive coding?

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@tkhurana tkhurana Jan 26, 2026

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In case of DistinctPrefix filter when column encoding is disabled we end up getting one cell (a non empty column cell) but found is also true. The DistinctPrefix filter ignores the empty cell so this is how we end up in this case where kvs.size()=1 and found is true but the cell being returned is not an empty column cell but some other cell.

// we found the empty cell, but it was not included so replace the existing cell
// with the empty column cell
kvs.remove(0);
kvs.add(emptyColumnCell);
}
}
}

Expand Down
57 changes: 57 additions & 0 deletions phoenix-core/src/it/java/org/apache/phoenix/end2end/EmptyColumnIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -31,10 +31,14 @@
import static org.apache.phoenix.query.PhoenixTestBuilder.SchemaBuilder.TenantViewOptions;
import static org.apache.phoenix.util.PhoenixRuntime.TENANT_ID_ATTRIB;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.Random;
Expand All @@ -46,13 +50,17 @@
import org.apache.hadoop.hbase.client.Scan;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.phoenix.jdbc.PhoenixResultSet;
import org.apache.phoenix.query.PhoenixTestBuilder.BasicDataWriter;
import org.apache.phoenix.query.PhoenixTestBuilder.DataSupplier;
import org.apache.phoenix.query.PhoenixTestBuilder.DataWriter;
import org.apache.phoenix.query.PhoenixTestBuilder.SchemaBuilder;
import org.apache.phoenix.query.QueryConstants;
import org.apache.phoenix.schema.PTable;
import org.apache.phoenix.util.EnvironmentEdgeManager;
import org.apache.phoenix.util.IndexUtil;
import org.apache.phoenix.util.ManualEnvironmentEdge;
import org.apache.phoenix.util.QueryUtil;
import org.apache.phoenix.util.SchemaUtil;
import org.apache.phoenix.util.TestUtil;
import org.junit.Ignore;
Expand Down Expand Up @@ -703,6 +711,55 @@ public List<Object> getValues(int rowIndex) {
}
}

/**
* Test that the empty column cell is returned by the scan when there is a DistinctPrefixFilter
* and an EmptyColumnOnlyFilter. If there is no empty column cell returned in the scan then TTL
* masking logic can break.
*/
@Test
public void testMaskingWithDistinctPrefixFilter() throws Exception {
try (Connection conn = DriverManager.getConnection(getUrl())) {
int ttl = 10;
String dataTableName = generateUniqueName();
// not using column encoding so that we use EmptyColumnOnlyFilter
String ddl = "create table " + dataTableName + " (id1 varchar(10) not null , "
+ "id2 varchar(10) not null , val1 varchar(10), val2 varchar(10) "
+ "constraint PK primary key (id1, id2)) COLUMN_ENCODED_BYTES=0, TTL=" + ttl;
conn.createStatement().execute(ddl);

String[] expectedValues = { "val1_1", "val1_2", "val1_3", "val1_4" };
String dml = "UPSERT INTO " + dataTableName + " VALUES(?, ?, ?, ?)";
PreparedStatement ps = conn.prepareStatement(dml);
for (int id1 = 0; id1 < 5; ++id1) {
ps.setString(1, "id1_" + id1);
for (int id2 = 0; id2 < 5; ++id2) {
ps.setString(2, "id2_" + id2);
ps.setString(3, "val1_" + id1 % 2);
ps.setString(4, "val2_" + id2 % 2);
ps.executeUpdate();
}
}
conn.commit();
try {
ManualEnvironmentEdge injectEdge = new ManualEnvironmentEdge();
// expire the rows
injectEdge.setValue(EnvironmentEdgeManager.currentTimeMillis() + ttl * 1000 + 2);
EnvironmentEdgeManager.injectEdge(injectEdge);
String distinctQuery = "SELECT DISTINCT id1 FROM " + dataTableName;
try (ResultSet rs = conn.createStatement().executeQuery(distinctQuery)) {
PhoenixResultSet prs = rs.unwrap(PhoenixResultSet.class);
String explainPlan = QueryUtil.getExplainPlan(prs.getUnderlyingIterator());
assertTrue(explainPlan.contains("SERVER FILTER BY EMPTY COLUMN ONLY"));
assertTrue(explainPlan.contains("SERVER DISTINCT PREFIX FILTER OVER"));
// all the rows should have been masked
assertFalse(rs.next());
}
} finally {
EnvironmentEdgeManager.reset();
}
}
}

private void upsertDataAndRunValidations(int numRowsToUpsert,
ExpectedTestResults expectedTestResults, DataWriter dataWriter, SchemaBuilder schemaBuilder,
List<Integer> overriddenColumnsPositions) throws Exception {
Expand Down
41 changes: 41 additions & 0 deletions phoenix-core/src/it/java/org/apache/phoenix/end2end/index/GlobalIndexCheckerIT.java
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Original file line number Diff line number Diff line change
Expand Up @@ -42,6 +42,7 @@
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Timestamp;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collection;
import java.util.List;
Expand All @@ -64,6 +65,7 @@
import org.apache.phoenix.util.ReadOnlyProps;
import org.apache.phoenix.util.TestUtil;
import org.junit.After;
import org.junit.Assume;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;
Expand Down Expand Up @@ -1661,6 +1663,45 @@ public void testOnDuplicateKeyWithIndex() throws Exception {
}
}

@Test
public void testWithDistinctPrefixFilter() throws Exception {
Assume.assumeTrue(async == false);
try (Connection conn = DriverManager.getConnection(getUrl())) {
String dataTableName = generateUniqueName();
String indexTableName = generateUniqueName();
String ddl = "create table " + dataTableName + " (id varchar(10) not null primary key, "
+ "val1 varchar(10), val2 varchar(10), val3 varchar(10))" + tableDDLOptions;
conn.createStatement().execute(ddl);
ddl = "create index " + indexTableName + " on " + dataTableName
+ " (val1) include (val2, val3)" + this.indexDDLOptions;
conn.createStatement().execute(ddl);
String[] expectedValues = { "val1_1", "val1_2", "val1_3", "val1_4" };
int rowCount = 20;
String dml = "UPSERT INTO " + dataTableName + " VALUES(?, ?, ?, ?)";
PreparedStatement ps = conn.prepareStatement(dml);
for (int id = 0; id < rowCount; ++id) {
ps.setString(1, "id_" + id);
ps.setString(2, expectedValues[id % expectedValues.length]);
ps.setString(3, "val2_" + id % 2);
ps.setString(4, "val3");
ps.executeUpdate();
}
conn.commit();
String distinctQuery = "SELECT DISTINCT val1 FROM " + dataTableName;
try (ResultSet rs = conn.createStatement().executeQuery(distinctQuery)) {
PhoenixResultSet prs = rs.unwrap(PhoenixResultSet.class);
String explainPlan = QueryUtil.getExplainPlan(prs.getUnderlyingIterator());
assertTrue(explainPlan.contains(indexTableName));
assertTrue(explainPlan.contains("SERVER DISTINCT PREFIX FILTER OVER"));
List actualValues = Lists.newArrayList();
while (rs.next()) {
actualValues.add(rs.getString(1));
}
assertEquals(Arrays.asList(expectedValues), actualValues);
}
}
}

public static void commitWithException(Connection conn) {
try {
conn.commit();
Expand Down