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Implement getTableStatistics for Oracle connector.
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‎presto-oracle/src/main/java/com/facebook/presto/plugin/oracle/OracleClient.java‎

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@@ -13,26 +13,41 @@
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*/
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package com.facebook.presto.plugin.oracle;
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import com.facebook.airlift.log.Logger;
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import com.facebook.presto.common.predicate.TupleDomain;
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import com.facebook.presto.common.type.Decimals;
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import com.facebook.presto.common.type.VarcharType;
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import com.facebook.presto.plugin.jdbc.BaseJdbcClient;
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import com.facebook.presto.plugin.jdbc.BaseJdbcConfig;
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import com.facebook.presto.plugin.jdbc.ConnectionFactory;
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import com.facebook.presto.plugin.jdbc.JdbcColumnHandle;
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import com.facebook.presto.plugin.jdbc.JdbcConnectorId;
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import com.facebook.presto.plugin.jdbc.JdbcIdentity;
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import com.facebook.presto.plugin.jdbc.JdbcTableHandle;
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import com.facebook.presto.plugin.jdbc.JdbcTypeHandle;
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import com.facebook.presto.plugin.jdbc.mapping.ReadMapping;
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import com.facebook.presto.spi.ColumnHandle;
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import com.facebook.presto.spi.ConnectorSession;
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import com.facebook.presto.spi.PrestoException;
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import com.facebook.presto.spi.SchemaTableName;
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import com.facebook.presto.spi.function.table.Preconditions;
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import com.facebook.presto.spi.statistics.ColumnStatistics;
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import com.facebook.presto.spi.statistics.DoubleRange;
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import com.facebook.presto.spi.statistics.Estimate;
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import com.facebook.presto.spi.statistics.TableStatistics;
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import com.google.common.collect.Maps;
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import jakarta.inject.Inject;
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import java.sql.Connection;
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import java.sql.DatabaseMetaData;
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import java.sql.Date;
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import java.sql.PreparedStatement;
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import java.sql.ResultSet;
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import java.sql.SQLException;
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import java.sql.Types;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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import static com.facebook.presto.common.type.DecimalType.createDecimalType;
@@ -46,13 +61,15 @@
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import static com.facebook.presto.plugin.jdbc.mapping.StandardColumnMappings.smallintReadMapping;
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import static com.facebook.presto.plugin.jdbc.mapping.StandardColumnMappings.varcharReadMapping;
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import static com.facebook.presto.spi.StandardErrorCode.NOT_SUPPORTED;
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import static java.lang.Double.NaN;
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import static java.lang.String.format;
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import static java.util.Locale.ENGLISH;
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import static java.util.Objects.requireNonNull;
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public class OracleClient
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extends BaseJdbcClient
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{
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private static final Logger LOG = Logger.get(OracleClient.class);
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private static final int FETCH_SIZE = 1000;
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private final boolean synonymsEnabled;
@@ -92,6 +109,7 @@ protected ResultSet getTables(Connection connection, Optional<String> schemaName
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escapeNamePattern(tableName, Optional.of(escape)).orElse(null),
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getTableTypes());
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}
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@Override
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public PreparedStatement getPreparedStatement(ConnectorSession session, Connection connection, String sql)
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throws SQLException
@@ -129,6 +147,99 @@ protected void renameTable(JdbcIdentity identity, String catalogName, SchemaTabl
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}
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}
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@Override
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public TableStatistics getTableStatistics(ConnectorSession session, JdbcTableHandle handle, List<JdbcColumnHandle> columnHandles, TupleDomain<ColumnHandle> tupleDomain)
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{
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try {
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Preconditions.checkNotNullOrEmpty(handle.getSchemaName(), "schema name");
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Preconditions.checkNotNullOrEmpty(handle.getTableName(), "table name");
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String sql = format(
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"SELECT NUM_ROWS, AVG_ROW_LEN, LAST_ANALYZED\n" +
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"FROM DBA_TAB_STATISTICS\n" +
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"WHERE OWNER='%s'\n" +
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"AND TABLE_NAME='%s'",
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handle.getSchemaName().toUpperCase(), handle.getTableName().toUpperCase());
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try (Connection connection = connectionFactory.openConnection(JdbcIdentity.from(session))) {
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PreparedStatement preparedStatement = getPreparedStatement(session, connection, sql);
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ResultSet resultSet = preparedStatement.executeQuery();
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if (!resultSet.next()) {
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LOG.debug("Stats not found for table : %s.%s", handle.getSchemaName(), handle.getTableName());
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return TableStatistics.empty();
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}
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double numRows = resultSet.getDouble("NUM_ROWS");
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double avgRowLen = resultSet.getDouble("AVG_ROW_LEN");
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Date lastAnalyzed = resultSet.getDate("LAST_ANALYZED");
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PreparedStatement preparedStatementCol = getPreparedStatement(session, connection, getColumnStaticsSql(handle));
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resultSet = preparedStatementCol.executeQuery();
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Map<ColumnHandle, ColumnStatistics> columnStatisticsMap = new HashMap<>();
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Map<String, JdbcColumnHandle> columnHandleMap = Maps.uniqueIndex(columnHandles, JdbcColumnHandle::getColumnName);
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while (resultSet.next() && numRows > 0) {
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String columnName = resultSet.getString("COLUMN_NAME");
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double nullsCount = resultSet.getDouble("NUM_NULLS");
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double ndv = resultSet.getDouble("NUM_DISTINCT");
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// 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
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// So we use column type as a clue and parse to double by converting as string first.
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double lowValue = toDouble(resultSet.getString("LOW_VALUE"));
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double highValue = toDouble(resultSet.getString("HIGH_VALUE"));
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ColumnStatistics.Builder columnStatisticsBuilder = ColumnStatistics.builder()
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.setDataSize(Estimate.estimateFromDouble(resultSet.getDouble("DATA_LENGTH")))
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.setNullsFraction(Estimate.estimateFromDouble(nullsCount / numRows))
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.setDistinctValuesCount(Estimate.estimateFromDouble(ndv));
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ColumnStatistics columnStatistics = columnStatisticsBuilder.build();
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if (Double.isFinite(lowValue) && Double.isFinite(highValue)) {
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columnStatistics = columnStatisticsBuilder.setRange(new DoubleRange(lowValue, highValue)).build();
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}
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columnStatisticsMap.put(columnHandleMap.get(columnName), columnStatistics);
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}
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resultSet.close();
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LOG.info("getTableStatics for table: %s.%s.%s with last analyzed: %s",
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handle.getCatalogName(), handle.getSchemaName(), handle.getTableName(), lastAnalyzed);
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return TableStatistics.builder()
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.setColumnStatistics(columnStatisticsMap)
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.setRowCount(Estimate.estimateFromDouble(numRows)).build();
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}
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}
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catch (SQLException | RuntimeException e) {
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throw new PrestoException(JDBC_ERROR, "Failed fetching statistics for table: " + handle, e);
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}
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}
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private String getColumnStaticsSql(JdbcTableHandle handle)
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{
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// UTL_RAW.CAST_TO_BINARY_X does not render correctly so those types are not supported.
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return format(
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"SELECT COLUMN_NAME,\n" +
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"DATA_TYPE,\n" +
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"DATA_LENGTH,\n" +
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"NUM_NULLS,\n" +
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"NUM_DISTINCT,\n" +
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"DENSITY,\n" +
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"CASE DATA_TYPE\n" +
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" WHEN 'NUMBER' THEN TO_CHAR(UTL_RAW.CAST_TO_NUMBER(LOW_VALUE))\n" +
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" ELSE NULL\n" +
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"END AS LOW_VALUE,\n" +
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"CASE DATA_TYPE\n" +
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" WHEN 'NUMBER' THEN TO_CHAR(UTL_RAW.CAST_TO_NUMBER(HIGH_VALUE))\n" +
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" ELSE NULL\n" +
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"END AS HIGH_VALUE\n" +
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"FROM ALL_TAB_COLUMNS\n" +
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"WHERE OWNER = '%s'\n" +
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" AND TABLE_NAME = '%s'", handle.getSchemaName().toUpperCase(), handle.getTableName().toUpperCase());
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}
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private double toDouble(String number)
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{
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try {
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return Double.parseDouble(number);
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}
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catch (Exception e) {
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// a string represented by number, may not even be a parseable number this is expected. e.g. if column type is
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// varchar.
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LOG.debug(e, "error while decoding : %s", number);
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}
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return NaN;
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}
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@Override
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public Optional<ReadMapping> toPrestoType(ConnectorSession session, JdbcTypeHandle typeHandle)
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{

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