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feat(plugin-oracle): Implemented getTableStatistics for oracle connector #26120

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Nov 3, 2025
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feat(plugin-oracle): Implemented getTableStatistics for oracle connector #26120

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110 changes: 110 additions & 0 deletions presto-oracle/src/main/java/com/facebook/presto/plugin/oracle/OracleClient.java
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Original file line number Diff line number Diff line change
Expand Up @@ -13,26 +13,40 @@
*/
package com.facebook.presto.plugin.oracle;

import com.facebook.airlift.log.Logger;
import com.facebook.presto.common.predicate.TupleDomain;
import com.facebook.presto.common.type.Decimals;
import com.facebook.presto.common.type.VarcharType;
import com.facebook.presto.plugin.jdbc.BaseJdbcClient;
import com.facebook.presto.plugin.jdbc.BaseJdbcConfig;
import com.facebook.presto.plugin.jdbc.ConnectionFactory;
import com.facebook.presto.plugin.jdbc.JdbcColumnHandle;
import com.facebook.presto.plugin.jdbc.JdbcConnectorId;
import com.facebook.presto.plugin.jdbc.JdbcIdentity;
import com.facebook.presto.plugin.jdbc.JdbcTableHandle;
import com.facebook.presto.plugin.jdbc.JdbcTypeHandle;
import com.facebook.presto.plugin.jdbc.mapping.ReadMapping;
import com.facebook.presto.spi.ColumnHandle;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.SchemaTableName;
import com.facebook.presto.spi.statistics.ColumnStatistics;
import com.facebook.presto.spi.statistics.DoubleRange;
import com.facebook.presto.spi.statistics.Estimate;
import com.facebook.presto.spi.statistics.TableStatistics;
import com.google.common.collect.Maps;
import jakarta.inject.Inject;

import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;

import static com.facebook.presto.common.type.DecimalType.createDecimalType;
Expand All @@ -47,13 +61,15 @@
import static com.facebook.presto.plugin.jdbc.mapping.StandardColumnMappings.varbinaryReadMapping;
import static com.facebook.presto.plugin.jdbc.mapping.StandardColumnMappings.varcharReadMapping;
import static com.facebook.presto.spi.StandardErrorCode.NOT_SUPPORTED;
import static java.lang.Double.NaN;
import static java.lang.String.format;
import static java.util.Locale.ENGLISH;
import static java.util.Objects.requireNonNull;

public class OracleClient
extends BaseJdbcClient
{
private static final Logger LOG = Logger.get(OracleClient.class);
private static final int FETCH_SIZE = 1000;

private final boolean synonymsEnabled;
Expand Down Expand Up @@ -93,6 +109,7 @@ protected ResultSet getTables(Connection connection, Optional<String> schemaName
escapeNamePattern(tableName, Optional.of(escape)).orElse(null),
getTableTypes());
}

@Override
public PreparedStatement getPreparedStatement(ConnectorSession session, Connection connection, String sql)
throws SQLException
Expand Down Expand Up @@ -137,6 +154,99 @@ protected void renameTable(JdbcIdentity identity, String catalogName, SchemaTabl
}
}

@Override
public TableStatistics getTableStatistics(ConnectorSession session, JdbcTableHandle handle, List<JdbcColumnHandle> columnHandles, TupleDomain<ColumnHandle> tupleDomain)
{
try {
requireNonNull(handle.getSchemaName(), "schema name is null");
requireNonNull(handle.getTableName(), "table name is null");
String sql = format(
"SELECT NUM_ROWS, AVG_ROW_LEN, LAST_ANALYZED\n" +
"FROM DBA_TAB_STATISTICS\n" +
"WHERE OWNER='%s'\n" +
"AND TABLE_NAME='%s'",
handle.getSchemaName().toUpperCase(), handle.getTableName().toUpperCase());
try (Connection connection = connectionFactory.openConnection(JdbcIdentity.from(session));
PreparedStatement preparedStatement = getPreparedStatement(session, connection, sql);
PreparedStatement preparedStatementCol = getPreparedStatement(session, connection, getColumnStaticsSql(handle));
ResultSet resultSet = preparedStatement.executeQuery();
ResultSet resultSetColumnStats = preparedStatementCol.executeQuery()) {
if (!resultSet.next()) {
LOG.debug("Stats not found for table : %s.%s", handle.getSchemaName(), handle.getTableName());
return TableStatistics.empty();
}
double numRows = resultSet.getDouble("NUM_ROWS");
// double avgRowLen = resultSet.getDouble("AVG_ROW_LEN");
Date lastAnalyzed = resultSet.getDate("LAST_ANALYZED");

Map<ColumnHandle, ColumnStatistics> columnStatisticsMap = new HashMap<>();
Map<String, JdbcColumnHandle> columnHandleMap = Maps.uniqueIndex(columnHandles, JdbcColumnHandle::getColumnName);
while (resultSetColumnStats.next() && numRows > 0) {
String columnName = resultSetColumnStats.getString("COLUMN_NAME");
double nullsCount = resultSetColumnStats.getDouble("NUM_NULLS");
double ndv = resultSetColumnStats.getDouble("NUM_DISTINCT");
// Oracle stores low and high values as RAW(1000) i.e. a byte array. No way to unwrap it, without a clue about the underlying type
// So we use column type as a clue and parse to double by converting as string first.
double lowValue = toDouble(resultSetColumnStats.getString("LOW_VALUE"));
double highValue = toDouble(resultSetColumnStats.getString("HIGH_VALUE"));
ColumnStatistics.Builder columnStatisticsBuilder = ColumnStatistics.builder()
.setDataSize(Estimate.estimateFromDouble(resultSet.getDouble("DATA_LENGTH")))
.setNullsFraction(Estimate.estimateFromDouble(nullsCount / numRows))
.setDistinctValuesCount(Estimate.estimateFromDouble(ndv));
ColumnStatistics columnStatistics = columnStatisticsBuilder.build();
if (Double.isFinite(lowValue) && Double.isFinite(highValue)) {
columnStatistics = columnStatisticsBuilder.setRange(new DoubleRange(lowValue, highValue)).build();
}
columnStatisticsMap.put(columnHandleMap.get(columnName), columnStatistics);
}
LOG.info("getTableStatics for table: %s.%s.%s with last analyzed: %s",
handle.getCatalogName(), handle.getSchemaName(), handle.getTableName(), lastAnalyzed);
return TableStatistics.builder()
.setColumnStatistics(columnStatisticsMap)
.setRowCount(Estimate.estimateFromDouble(numRows)).build();
}
}
catch (SQLException | RuntimeException e) {
throw new PrestoException(JDBC_ERROR, "Failed fetching statistics for table: " + handle, e);
}
}

private String getColumnStaticsSql(JdbcTableHandle handle)
{
// UTL_RAW.CAST_TO_BINARY_X does not render correctly so those types are not supported.
return format(
"SELECT COLUMN_NAME,\n" +
"DATA_TYPE,\n" +
"DATA_LENGTH,\n" +
"NUM_NULLS,\n" +
"NUM_DISTINCT,\n" +
"DENSITY,\n" +
"CASE DATA_TYPE\n" +
" WHEN 'NUMBER' THEN TO_CHAR(UTL_RAW.CAST_TO_NUMBER(LOW_VALUE))\n" +
" ELSE NULL\n" +
"END AS LOW_VALUE,\n" +
"CASE DATA_TYPE\n" +
" WHEN 'NUMBER' THEN TO_CHAR(UTL_RAW.CAST_TO_NUMBER(HIGH_VALUE))\n" +
" ELSE NULL\n" +
"END AS HIGH_VALUE\n" +
"FROM ALL_TAB_COLUMNS\n" +
"WHERE OWNER = '%s'\n" +
" AND TABLE_NAME = '%s'", handle.getSchemaName().toUpperCase(), handle.getTableName().toUpperCase());
}

private double toDouble(String number)
{
try {
return Double.parseDouble(number);
}
catch (Exception e) {
// a string represented by number, may not even be a parseable number this is expected. e.g. if column type is
// varchar.
LOG.debug(e, "error while decoding : %s", number);
}
return NaN;
}

@Override
public Optional<ReadMapping> toPrestoType(ConnectorSession session, JdbcTypeHandle typeHandle)
{
Expand Down
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