/*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.facebook.presto.accumulo;
import com.facebook.presto.accumulo.conf.AccumuloConfig;
import com.facebook.presto.accumulo.conf.AccumuloSessionProperties;
import com.facebook.presto.accumulo.conf.AccumuloTableProperties;
import com.facebook.presto.accumulo.index.IndexLookup;
import com.facebook.presto.accumulo.index.Indexer;
import com.facebook.presto.accumulo.io.AccumuloPageSink;
import com.facebook.presto.accumulo.metadata.AccumuloTable;
import com.facebook.presto.accumulo.metadata.AccumuloView;
import com.facebook.presto.accumulo.metadata.ZooKeeperMetadataManager;
import com.facebook.presto.accumulo.model.AccumuloColumnConstraint;
import com.facebook.presto.accumulo.model.AccumuloColumnHandle;
import com.facebook.presto.accumulo.model.TabletSplitMetadata;
import com.facebook.presto.accumulo.serializers.AccumuloRowSerializer;
import com.facebook.presto.spi.ColumnMetadata;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.ConnectorTableMetadata;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.SchemaTableName;
import com.facebook.presto.spi.TableNotFoundException;
import com.facebook.presto.spi.predicate.Domain;
import com.facebook.presto.spi.predicate.Marker.Bound;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;
import io.airlift.log.Logger;
import org.apache.accumulo.core.client.AccumuloException;
import org.apache.accumulo.core.client.AccumuloSecurityException;
import org.apache.accumulo.core.client.Connector;
import org.apache.accumulo.core.client.IteratorSetting;
import org.apache.accumulo.core.client.Scanner;
import org.apache.accumulo.core.data.Key;
import org.apache.accumulo.core.data.PartialKey;
import org.apache.accumulo.core.data.Range;
import org.apache.accumulo.core.data.Value;
import org.apache.accumulo.core.security.Authorizations;
import org.apache.commons.lang3.tuple.Pair;
import org.apache.hadoop.io.Text;
import javax.inject.Inject;
import java.security.InvalidParameterException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Optional;
import java.util.Set;
import java.util.stream.Collectors;
import static com.facebook.presto.accumulo.AccumuloErrorCode.ACCUMULO_TABLE_DNE;
import static com.facebook.presto.accumulo.AccumuloErrorCode.ACCUMULO_TABLE_EXISTS;
import static com.facebook.presto.accumulo.AccumuloErrorCode.UNEXPECTED_ACCUMULO_ERROR;
import static com.facebook.presto.spi.StandardErrorCode.ALREADY_EXISTS;
import static com.facebook.presto.spi.StandardErrorCode.FUNCTION_IMPLEMENTATION_ERROR;
import static com.facebook.presto.spi.StandardErrorCode.INVALID_TABLE_PROPERTY;
import static com.facebook.presto.spi.StandardErrorCode.INVALID_VIEW;
import static com.facebook.presto.spi.StandardErrorCode.NOT_FOUND;
import static com.facebook.presto.spi.StandardErrorCode.NOT_SUPPORTED;
import static java.lang.String.format;
import static java.util.Objects.requireNonNull;
/**
* This class is the main access point for the Presto connector to interact with Accumulo.
* It is responsible for creating tables, dropping tables, retrieving table metadata, and getting the ConnectorSplits from a table.
*/
public class AccumuloClient
{
private static final Logger LOG = Logger.get(AccumuloClient.class);
private static final Splitter COMMA_SPLITTER = Splitter.on(',').omitEmptyStrings().trimResults();
private final ZooKeeperMetadataManager metaManager;
private final Authorizations auths;
private final AccumuloTableManager tableManager;
private final Connector connector;
private final IndexLookup indexLookup;
private final String username;
@Inject
public AccumuloClient(
Connector connector,
AccumuloConfig config,
ZooKeeperMetadataManager metaManager,
AccumuloTableManager tableManager,
IndexLookup indexLookup)
throws AccumuloException, AccumuloSecurityException
{
this.connector = requireNonNull(connector, "connector is null");
this.username = requireNonNull(config, "config is null").getUsername();
this.metaManager = requireNonNull(metaManager, "metaManager is null");
this.tableManager = requireNonNull(tableManager, "tableManager is null");
this.indexLookup = requireNonNull(indexLookup, "indexLookup is null");
this.auths = connector.securityOperations().getUserAuthorizations(username);
}
public AccumuloTable createTable(ConnectorTableMetadata meta)
{
// Validate the DDL is something we can handle
validateCreateTable(meta);
Map<String, Object> tableProperties = meta.getProperties();
String rowIdColumn = getRowIdColumn(meta);
// Get the list of column handles
List<AccumuloColumnHandle> columns = getColumnHandles(meta, rowIdColumn);
// Create the AccumuloTable object
AccumuloTable table = new AccumuloTable(
meta.getTable().getSchemaName(),
meta.getTable().getTableName(),
columns,
rowIdColumn,
AccumuloTableProperties.isExternal(tableProperties),
AccumuloTableProperties.getSerializerClass(tableProperties),
AccumuloTableProperties.getScanAuthorizations(tableProperties));
// First, create the metadata
metaManager.createTableMetadata(table);
// Make sure the namespace exists
tableManager.ensureNamespace(table.getSchema());
// Create the Accumulo table if it does not exist (for 'external' table)
if (!tableManager.exists(table.getFullTableName())) {
tableManager.createAccumuloTable(table.getFullTableName());
}
// Set any locality groups on the data table
setLocalityGroups(tableProperties, table);
// Create index tables, if appropriate
createIndexTables(table);
return table;
}
/**
* Validates the given metadata for a series of conditions to ensure the table is well-formed.
*
* @param meta Table metadata
*/
private void validateCreateTable(ConnectorTableMetadata meta)
{
validateColumns(meta);
validateLocalityGroups(meta);
if (!AccumuloTableProperties.isExternal(meta.getProperties())) {
validateInternalTable(meta);
}
}
private static void validateColumns(ConnectorTableMetadata meta)
{
// Check all the column types, and throw an exception if the types of a map are complex
// While it is a rare case, this is not supported by the Accumulo connector
ImmutableSet.Builder<String> columnNameBuilder = ImmutableSet.builder();
for (ColumnMetadata column : meta.getColumns()) {
if (Types.isMapType(column.getType())) {
if (Types.isMapType(Types.getKeyType(column.getType()))
|| Types.isMapType(Types.getValueType(column.getType()))
|| Types.isArrayType(Types.getKeyType(column.getType()))
|| Types.isArrayType(Types.getValueType(column.getType()))) {
throw new PrestoException(INVALID_TABLE_PROPERTY, "Key/value types of a MAP column must be plain types");
}
}
columnNameBuilder.add(column.getName().toLowerCase(Locale.ENGLISH));
}
// Validate the columns are distinct
if (columnNameBuilder.build().size() != meta.getColumns().size()) {
throw new PrestoException(INVALID_TABLE_PROPERTY, "Duplicate column names are not supported");
}
Optional<Map<String, Pair<String, String>>> columnMapping = AccumuloTableProperties.getColumnMapping(meta.getProperties());
if (columnMapping.isPresent()) {
// Validate there are no duplicates in the column mapping
long distinctMappings = columnMapping.get().values().stream().distinct().count();
if (distinctMappings != columnMapping.get().size()) {
throw new PrestoException(INVALID_TABLE_PROPERTY, "Duplicate column family/qualifier pair detected in column mapping, check the value of " + AccumuloTableProperties.COLUMN_MAPPING);
}
// Validate no column is mapped to the reserved entry
String reservedRowIdColumn = AccumuloPageSink.ROW_ID_COLUMN.toString();
if (columnMapping.get().values().stream()
.filter(pair -> pair.getKey().equals(reservedRowIdColumn) && pair.getValue().equals(reservedRowIdColumn))
.count() > 0) {
throw new PrestoException(INVALID_TABLE_PROPERTY, format("Column familiy/qualifier mapping of %s:%s is reserved", reservedRowIdColumn, reservedRowIdColumn));
}
}
else if (AccumuloTableProperties.isExternal(meta.getProperties())) {
// Column mapping is not defined (i.e. use column generation) and table is external
// But column generation is for internal tables only
throw new PrestoException(INVALID_TABLE_PROPERTY, "Column generation for external tables is not supported, must specify " + AccumuloTableProperties.COLUMN_MAPPING);
}
}
private static void validateLocalityGroups(ConnectorTableMetadata meta)
{
// Validate any configured locality groups
Optional<Map<String, Set<String>>> groups = AccumuloTableProperties.getLocalityGroups(meta.getProperties());
if (!groups.isPresent()) {
return;
}
String rowIdColumn = getRowIdColumn(meta);
// For each locality group
for (Map.Entry<String, Set<String>> g : groups.get().entrySet()) {
if (g.getValue().contains(rowIdColumn)) {
throw new PrestoException(INVALID_TABLE_PROPERTY, "Row ID column cannot be in a locality group");
}
// Validate the specified column names exist in the table definition,
// incrementing a counter for each matching column
int matchingColumns = 0;
for (ColumnMetadata column : meta.getColumns()) {
if (g.getValue().contains(column.getName().toLowerCase(Locale.ENGLISH))) {
++matchingColumns;
// Break out early if all columns are found
if (matchingColumns == g.getValue().size()) {
break;
}
}
}
// If the number of matched columns does not equal the defined size,
// then a column was specified that does not exist
// (or there is a duplicate column in the table DDL, which is also an issue but has been checked before in validateColumns).
if (matchingColumns != g.getValue().size()) {
throw new PrestoException(INVALID_TABLE_PROPERTY, "Unknown Presto column defined for locality group " + g.getKey());
}
}
}
private void validateInternalTable(ConnectorTableMetadata meta)
{
String table = AccumuloTable.getFullTableName(meta.getTable());
String indexTable = Indexer.getIndexTableName(meta.getTable());
String metricsTable = Indexer.getMetricsTableName(meta.getTable());
if (tableManager.exists(table)) {
throw new PrestoException(ACCUMULO_TABLE_EXISTS, "Cannot create internal table when an Accumulo table already exists");
}
if (AccumuloTableProperties.getIndexColumns(meta.getProperties()).isPresent()) {
if (tableManager.exists(indexTable) || tableManager.exists(metricsTable)) {
throw new PrestoException(ACCUMULO_TABLE_EXISTS, "Internal table is indexed, but the index table and/or index metrics table(s) already exist");
}
}
}
/**
* Gets the row ID based on a table properties or the first column name.
*
* @param meta ConnectorTableMetadata
* @return Lowercase Presto column name mapped to the Accumulo row ID
*/
private static String getRowIdColumn(ConnectorTableMetadata meta)
{
Optional<String> rowIdColumn = AccumuloTableProperties.getRowId(meta.getProperties());
return rowIdColumn.orElse(meta.getColumns().get(0).getName()).toLowerCase(Locale.ENGLISH);
}
private static List<AccumuloColumnHandle> getColumnHandles(ConnectorTableMetadata meta, String rowIdColumn)
{
// Get the column mappings from the table property or auto-generate columns if not defined
Map<String, Pair<String, String>> mapping = AccumuloTableProperties.getColumnMapping(meta.getProperties()).orElse(autoGenerateMapping(meta.getColumns(), AccumuloTableProperties.getLocalityGroups(meta.getProperties())));
// The list of indexed columns
Optional<List<String>> indexedColumns = AccumuloTableProperties.getIndexColumns(meta.getProperties());
// And now we parse the configured columns and create handles for the metadata manager
ImmutableList.Builder<AccumuloColumnHandle> cBuilder = ImmutableList.builder();
for (int ordinal = 0; ordinal < meta.getColumns().size(); ++ordinal) {
ColumnMetadata cm = meta.getColumns().get(ordinal);
// Special case if this column is the row ID
if (cm.getName().equalsIgnoreCase(rowIdColumn)) {
cBuilder.add(
new AccumuloColumnHandle(
rowIdColumn,
Optional.empty(),
Optional.empty(),
cm.getType(),
ordinal,
"Accumulo row ID",
false));
}
else {
if (!mapping.containsKey(cm.getName())) {
throw new InvalidParameterException(format("Misconfigured mapping for presto column %s", cm.getName()));
}
// Get the mapping for this column
Pair<String, String> famqual = mapping.get(cm.getName());
boolean indexed = indexedColumns.isPresent() && indexedColumns.get().contains(cm.getName().toLowerCase(Locale.ENGLISH));
String comment = format("Accumulo column %s:%s. Indexed: %b", famqual.getLeft(), famqual.getRight(), indexed);
// Create a new AccumuloColumnHandle object
cBuilder.add(
new AccumuloColumnHandle(
cm.getName(),
Optional.of(famqual.getLeft()),
Optional.of(famqual.getRight()),
cm.getType(),
ordinal,
comment,
indexed));
}
}
return cBuilder.build();
}
private void setLocalityGroups(Map<String, Object> tableProperties, AccumuloTable table)
{
Optional<Map<String, Set<String>>> groups = AccumuloTableProperties.getLocalityGroups(tableProperties);
if (!groups.isPresent()) {
LOG.debug("No locality groups to set");
return;
}
ImmutableMap.Builder<String, Set<Text>> localityGroupsBuilder = ImmutableMap.builder();
for (Map.Entry<String, Set<String>> g : groups.get().entrySet()) {
ImmutableSet.Builder<Text> familyBuilder = ImmutableSet.builder();
// For each configured column for this locality group
for (String col : g.getValue()) {
// Locate the column family mapping via the Handle
// We already validated this earlier, so it'll exist
AccumuloColumnHandle handle = table.getColumns()
.stream()
.filter(x -> x.getName().equals(col))
.collect(Collectors.toList())
.get(0);
familyBuilder.add(new Text(handle.getFamily().get()));
}
localityGroupsBuilder.put(g.getKey(), familyBuilder.build());
}
Map<String, Set<Text>> localityGroups = localityGroupsBuilder.build();
LOG.debug("Setting locality groups: {}", localityGroups);
tableManager.setLocalityGroups(table.getFullTableName(), localityGroups);
}
/**
* Creates the index tables from the given Accumulo table. No op if
* {@link AccumuloTable#isIndexed()} is false.
*
* @param table Table to create index tables
*/
private void createIndexTables(AccumuloTable table)
{
// Early-out if table is not indexed
if (!table.isIndexed()) {
return;
}
// Create index table if it does not exist (for 'external' table)
if (!tableManager.exists(table.getIndexTableName())) {
tableManager.createAccumuloTable(table.getIndexTableName());
}
// Create index metrics table if it does not exist
if (!tableManager.exists(table.getMetricsTableName())) {
tableManager.createAccumuloTable(table.getMetricsTableName());
}
// Set locality groups on index and metrics table
Map<String, Set<Text>> indexGroups = Indexer.getLocalityGroups(table);
tableManager.setLocalityGroups(table.getIndexTableName(), indexGroups);
tableManager.setLocalityGroups(table.getMetricsTableName(), indexGroups);
// Attach iterators to metrics table
for (IteratorSetting setting : Indexer.getMetricIterators(table)) {
tableManager.setIterator(table.getMetricsTableName(), setting);
}
}
/**
* Auto-generates the mapping of Presto column name to Accumulo family/qualifier, respecting the locality groups (if any).
*
* @param columns Presto columns for the table
* @param groups Mapping of locality groups to a set of Presto columns, or null if none
* @return Column mappings
*/
private static Map<String, Pair<String, String>> autoGenerateMapping(List<ColumnMetadata> columns, Optional<Map<String, Set<String>>> groups)
{
Map<String, Pair<String, String>> mapping = new HashMap<>();
for (ColumnMetadata column : columns) {
Optional<String> family = getColumnLocalityGroup(column.getName(), groups);
mapping.put(column.getName(), Pair.of(family.orElse(column.getName()), column.getName()));
}
return mapping;
}
/**
* Searches through the given locality groups to find if this column has a locality group.
*
* @param columnName Column name to get the locality group of
* @param groups Optional locality group configuration
* @return Optional string containing the name of the locality group, if present
*/
private static Optional<String> getColumnLocalityGroup(String columnName, Optional<Map<String, Set<String>>> groups)
{
if (groups.isPresent()) {
for (Map.Entry<String, Set<String>> group : groups.get().entrySet()) {
if (group.getValue().contains(columnName.toLowerCase(Locale.ENGLISH))) {
return Optional.of(group.getKey());
}
}
}
return Optional.empty();
}
public void dropTable(AccumuloTable table)
{
SchemaTableName tableName = new SchemaTableName(table.getSchema(), table.getTable());
// Remove the table metadata from Presto
if (metaManager.getTable(tableName) != null) {
metaManager.deleteTableMetadata(tableName);
}
if (!table.isExternal()) {
// delete the table and index tables
String fullTableName = table.getFullTableName();
if (tableManager.exists(fullTableName)) {
tableManager.deleteAccumuloTable(fullTableName);
}
if (table.isIndexed()) {
String indexTableName = Indexer.getIndexTableName(tableName);
if (tableManager.exists(indexTableName)) {
tableManager.deleteAccumuloTable(indexTableName);
}
String metricsTableName = Indexer.getMetricsTableName(tableName);
if (tableManager.exists(metricsTableName)) {
tableManager.deleteAccumuloTable(metricsTableName);
}
}
}
}
public void renameTable(SchemaTableName oldName, SchemaTableName newName)
{
if (!oldName.getSchemaName().equals(newName.getSchemaName())) {
throw new PrestoException(NOT_SUPPORTED, "Accumulo does not support renaming tables to different namespaces (schemas)");
}
AccumuloTable oldTable = getTable(oldName);
if (oldTable == null) {
throw new TableNotFoundException(oldName);
}
AccumuloTable newTable = new AccumuloTable(
oldTable.getSchema(),
newName.getTableName(),
oldTable.getColumns(),
oldTable.getRowId(),
oldTable.isExternal(),
oldTable.getSerializerClassName(),
oldTable.getScanAuthorizations());
// Validate table existence
if (!tableManager.exists(oldTable.getFullTableName())) {
throw new PrestoException(ACCUMULO_TABLE_DNE, format("Table %s does not exist", oldTable.getFullTableName()));
}
if (tableManager.exists(newTable.getFullTableName())) {
throw new PrestoException(ACCUMULO_TABLE_EXISTS, format("Table %s already exists", newTable.getFullTableName()));
}
// Rename index tables (which will also validate table existence)
renameIndexTables(oldTable, newTable);
// Rename the Accumulo table
tableManager.renameAccumuloTable(oldTable.getFullTableName(), newTable.getFullTableName());
// We'll then create the metadata
metaManager.deleteTableMetadata(oldTable.getSchemaTableName());
metaManager.createTableMetadata(newTable);
}
/**
* Renames the index tables (if applicable) for the old table to the new table.
*
* @param oldTable Old AccumuloTable
* @param newTable New AccumuloTable
*/
private void renameIndexTables(AccumuloTable oldTable, AccumuloTable newTable)
{
if (!oldTable.isIndexed()) {
return;
}
if (!tableManager.exists(oldTable.getIndexTableName())) {
throw new PrestoException(ACCUMULO_TABLE_DNE, format("Table %s does not exist", oldTable.getIndexTableName()));
}
if (tableManager.exists(newTable.getIndexTableName())) {
throw new PrestoException(ACCUMULO_TABLE_EXISTS, format("Table %s already exists", newTable.getIndexTableName()));
}
if (!tableManager.exists(oldTable.getMetricsTableName())) {
throw new PrestoException(ACCUMULO_TABLE_DNE, format("Table %s does not exist", oldTable.getMetricsTableName()));
}
if (tableManager.exists(newTable.getMetricsTableName())) {
throw new PrestoException(ACCUMULO_TABLE_EXISTS, format("Table %s already exists", newTable.getMetricsTableName()));
}
tableManager.renameAccumuloTable(oldTable.getIndexTableName(), newTable.getIndexTableName());
tableManager.renameAccumuloTable(oldTable.getMetricsTableName(), newTable.getMetricsTableName());
}
public void createView(SchemaTableName viewName, String viewData)
{
if (getSchemaNames().contains(viewName.getSchemaName())) {
if (getViewNames(viewName.getSchemaName()).contains(viewName.getTableName())) {
throw new PrestoException(ALREADY_EXISTS, "View already exists");
}
if (getTableNames(viewName.getSchemaName()).contains(viewName.getTableName())) {
throw new PrestoException(INVALID_VIEW, "View already exists as data table");
}
}
metaManager.createViewMetadata(new AccumuloView(viewName.getSchemaName(), viewName.getTableName(), viewData));
}
public void createOrReplaceView(SchemaTableName viewName, String viewData)
{
if (getView(viewName) != null) {
metaManager.deleteViewMetadata(viewName);
}
metaManager.createViewMetadata(new AccumuloView(viewName.getSchemaName(), viewName.getTableName(), viewData));
}
public void dropView(SchemaTableName viewName)
{
metaManager.deleteViewMetadata(viewName);
}
public void renameColumn(AccumuloTable table, String source, String target)
{
if (!table.getColumns().stream().anyMatch(columnHandle -> columnHandle.getName().equalsIgnoreCase(source))) {
throw new PrestoException(NOT_FOUND, format("Failed to find source column %s to rename to %s", source, target));
}
// Copy existing column list, replacing the old column name with the new
ImmutableList.Builder<AccumuloColumnHandle> newColumnList = ImmutableList.builder();
for (AccumuloColumnHandle columnHandle : table.getColumns()) {
if (columnHandle.getName().equalsIgnoreCase(source)) {
newColumnList.add(new AccumuloColumnHandle(
target,
columnHandle.getFamily(),
columnHandle.getQualifier(),
columnHandle.getType(),
columnHandle.getOrdinal(),
columnHandle.getComment(),
columnHandle.isIndexed()));
}
else {
newColumnList.add(columnHandle);
}
}
// Create new table metadata
AccumuloTable newTable = new AccumuloTable(
table.getSchema(),
table.getTable(),
newColumnList.build(),
table.getRowId().equalsIgnoreCase(source) ? target : table.getRowId(),
table.isExternal(),
table.getSerializerClassName(),
table.getScanAuthorizations());
// Replace the table metadata
metaManager.deleteTableMetadata(new SchemaTableName(table.getSchema(), table.getTable()));
metaManager.createTableMetadata(newTable);
}
public Set<String> getSchemaNames()
{
return metaManager.getSchemaNames();
}
public Set<String> getTableNames(String schema)
{
requireNonNull(schema, "schema is null");
return metaManager.getTableNames(schema);
}
public AccumuloTable getTable(SchemaTableName table)
{
requireNonNull(table, "schema table name is null");
return metaManager.getTable(table);
}
public Set<String> getViewNames(String schema)
{
requireNonNull(schema, "schema is null");
return metaManager.getViewNames(schema);
}
public AccumuloView getView(SchemaTableName viewName)
{
requireNonNull(viewName, "schema table name is null");
return metaManager.getView(viewName);
}
/**
* Fetches the TabletSplitMetadata for a query against an Accumulo table.
* <p>
* Does a whole bunch of fun stuff! Splitting on row ID ranges, applying secondary indexes, column pruning,
* all sorts of sweet optimizations. What you have here is an important method.
*
* @param session Current session
* @param schema Schema name
* @param table Table Name
* @param rowIdDomain Domain for the row ID
* @param constraints Column constraints for the query
* @param serializer Instance of a row serializer
* @return List of TabletSplitMetadata objects for Presto
*/
public List<TabletSplitMetadata> getTabletSplits(
ConnectorSession session,
String schema,
String table,
Optional<Domain> rowIdDomain,
List<AccumuloColumnConstraint> constraints,
AccumuloRowSerializer serializer)
{
try {
String tableName = AccumuloTable.getFullTableName(schema, table);
LOG.debug("Getting tablet splits for table %s", tableName);
// Get the initial Range based on the row ID domain
Collection<Range> rowIdRanges = getRangesFromDomain(rowIdDomain, serializer);
List<TabletSplitMetadata> tabletSplits = new ArrayList<>();
// Use the secondary index, if enabled
if (AccumuloSessionProperties.isOptimizeIndexEnabled(session)) {
// Get the scan authorizations to query the index
Authorizations auths = getScanAuthorizations(session, schema, table);
// Check the secondary index based on the column constraints
// If this returns true, return the tablet splits to Presto
if (indexLookup.applyIndex(schema, table, session, constraints, rowIdRanges, tabletSplits, serializer, auths)) {
return tabletSplits;
}
}
// If we can't (or shouldn't) use the secondary index, we will just use the Range from the row ID domain
// Split the ranges on tablet boundaries, if enabled
Collection<Range> splitRanges;
if (AccumuloSessionProperties.isOptimizeSplitRangesEnabled(session)) {
splitRanges = splitByTabletBoundaries(tableName, rowIdRanges);
}
else {
// if not enabled, just use the same collection
splitRanges = rowIdRanges;
}
// Create TabletSplitMetadata objects for each range
boolean fetchTabletLocations = AccumuloSessionProperties.isOptimizeLocalityEnabled(session);
LOG.debug("Fetching tablet locations: %s", fetchTabletLocations);
for (Range range : splitRanges) {
// If locality is enabled, then fetch tablet location
if (fetchTabletLocations) {
tabletSplits.add(new TabletSplitMetadata(getTabletLocation(tableName, range.getStartKey()), ImmutableList.of(range)));
}
else {
// else, just use the default location
tabletSplits.add(new TabletSplitMetadata(Optional.empty(), ImmutableList.of(range)));
}
}
// Log some fun stuff and return the tablet splits
LOG.debug("Number of splits for table %s is %d with %d ranges", tableName, tabletSplits.size(), splitRanges.size());
return tabletSplits;
}
catch (Exception e) {
throw new PrestoException(UNEXPECTED_ACCUMULO_ERROR, "Failed to get splits from Accumulo", e);
}
}
/**
* Gets the scan authorizations to use for scanning tables.
* <p>
* In order of priority: session username authorizations, then table property, then the default connector auths.
*
* @param session Current session
* @param schema Schema name
* @param table Table Name
* @return Scan authorizations
* @throws AccumuloException If a generic Accumulo error occurs
* @throws AccumuloSecurityException If a security exception occurs
*/
private Authorizations getScanAuthorizations(ConnectorSession session, String schema,
String table)
throws AccumuloException, AccumuloSecurityException
{
String sessionScanUser = AccumuloSessionProperties.getScanUsername(session);
if (sessionScanUser != null) {
Authorizations scanAuths = connector.securityOperations().getUserAuthorizations(sessionScanUser);
LOG.debug("Using session scan auths for user %s: %s", sessionScanUser, scanAuths);
return scanAuths;
}
AccumuloTable accumuloTable = this.getTable(new SchemaTableName(schema, table));
if (accumuloTable == null) {
throw new TableNotFoundException(new SchemaTableName(schema, table));
}
Optional<String> strAuths = accumuloTable.getScanAuthorizations();
if (strAuths.isPresent()) {
Authorizations scanAuths = new Authorizations(Iterables.toArray(COMMA_SPLITTER.split(strAuths.get()), String.class));
LOG.debug("scan_auths table property set, using: %s", scanAuths);
return scanAuths;
}
LOG.debug("scan_auths table property not set, using connector auths: %s", this.auths);
return this.auths;
}
private Collection<Range> splitByTabletBoundaries(String tableName, Collection<Range> ranges)
throws org.apache.accumulo.core.client.TableNotFoundException, AccumuloException, AccumuloSecurityException
{
ImmutableSet.Builder<Range> rangeBuilder = ImmutableSet.builder();
for (Range range : ranges) {
// if start and end key are equivalent, no need to split the range
if (range.getStartKey() != null && range.getEndKey() != null && range.getStartKey().equals(range.getEndKey())) {
rangeBuilder.add(range);
}
else {
// Call out to Accumulo to split the range on tablets
rangeBuilder.addAll(connector.tableOperations().splitRangeByTablets(tableName, range, Integer.MAX_VALUE));
}
}
return rangeBuilder.build();
}
/**
* Gets the TabletServer hostname for where the given key is located in the given table
*
* @param table Fully-qualified table name
* @param key Key to locate
* @return The tablet location, or DUMMY_LOCATION if an error occurs
*/
private Optional<String> getTabletLocation(String table, Key key)
{
try {
// Get the Accumulo table ID so we can scan some fun stuff
String tableId = connector.tableOperations().tableIdMap().get(table);
// Create our scanner against the metadata table, fetching 'loc' family
Scanner scanner = connector.createScanner("accumulo.metadata", auths);
scanner.fetchColumnFamily(new Text("loc"));
// Set the scan range to just this table, from the table ID to the default tablet
// row, which is the last listed tablet
Key defaultTabletRow = new Key(tableId + '<');
Key start = new Key(tableId);
Key end = defaultTabletRow.followingKey(PartialKey.ROW);
scanner.setRange(new Range(start, end));
Optional<String> location = Optional.empty();
if (key == null) {
// if the key is null, then it is -inf, so get first tablet location
Iterator<Entry<Key, Value>> iter = scanner.iterator();
if (iter.hasNext()) {
location = Optional.of(iter.next().getValue().toString());
}
}
else {
// Else, we will need to scan through the tablet location data and find the location
// Create some text objects to do comparison for what we are looking for
Text splitCompareKey = new Text();
key.getRow(splitCompareKey);
Text scannedCompareKey = new Text();
// Scan the table!
for (Entry<Key, Value> entry : scanner) {
// Get the bytes of the key
byte[] keyBytes = entry.getKey().getRow().copyBytes();
// If the last byte is <, then we have hit the default tablet, so use this location
if (keyBytes[keyBytes.length - 1] == '<') {
location = Optional.of(entry.getValue().toString());
break;
}
else {
// Chop off some magic nonsense
scannedCompareKey.set(keyBytes, 3, keyBytes.length - 3);
// Compare the keys, moving along the tablets until the location is found
if (scannedCompareKey.getLength() > 0) {
int compareTo = splitCompareKey.compareTo(scannedCompareKey);
if (compareTo <= 0) {
location = Optional.of(entry.getValue().toString());
}
else {
// all future tablets will be greater than this key
break;
}
}
}
}
scanner.close();
}
// If we were unable to find the location for some reason, return the default tablet
// location
return location.isPresent() ? location : getDefaultTabletLocation(table);
}
catch (Exception e) {
// Swallow this exception so the query does not fail due to being unable
// to locate the tablet server for the provided Key.
// This is purely an optimization, but we will want to log the error.
LOG.error("Failed to get tablet location, returning dummy location", e);
return Optional.empty();
}
}
private Optional<String> getDefaultTabletLocation(String fulltable)
{
try {
String tableId = connector.tableOperations().tableIdMap().get(fulltable);
// Create a scanner over the metadata table, fetching the 'loc' column of the default tablet row
Scanner scan = connector.createScanner("accumulo.metadata", connector.securityOperations().getUserAuthorizations(username));
scan.fetchColumnFamily(new Text("loc"));
scan.setRange(new Range(tableId + '<'));
// scan the entry
Optional<String> location = Optional.empty();
for (Entry<Key, Value> entry : scan) {
if (location.isPresent()) {
throw new PrestoException(FUNCTION_IMPLEMENTATION_ERROR, "Scan for default tablet returned more than one entry");
}
location = Optional.of(entry.getValue().toString());
}
scan.close();
return location;
}
catch (Exception e) {
// Swallow this exception so the query does not fail due to being unable to locate the tablet server for the default tablet.
// This is purely an optimization, but we will want to log the error.
LOG.error("Failed to get tablet location, returning dummy location", e);
return Optional.empty();
}
}
/**
* Gets a collection of Accumulo Range objects from the given Presto domain.
* This maps the column constraints of the given Domain to an Accumulo Range scan.
*
* @param domain Domain, can be null (returns (-inf, +inf) Range)
* @param serializer Instance of an {@link AccumuloRowSerializer}
* @return A collection of Accumulo Range objects
* @throws TableNotFoundException If the Accumulo table is not found
*/
public static Collection<Range> getRangesFromDomain(Optional<Domain> domain, AccumuloRowSerializer serializer)
throws TableNotFoundException
{
// if we have no predicate pushdown, use the full range
if (!domain.isPresent()) {
return ImmutableSet.of(new Range());
}
ImmutableSet.Builder<Range> rangeBuilder = ImmutableSet.builder();
for (com.facebook.presto.spi.predicate.Range range : domain.get().getValues().getRanges().getOrderedRanges()) {
rangeBuilder.add(getRangeFromPrestoRange(range, serializer));
}
return rangeBuilder.build();
}
private static Range getRangeFromPrestoRange(com.facebook.presto.spi.predicate.Range prestoRange, AccumuloRowSerializer serializer)
throws TableNotFoundException
{
Range accumuloRange;
if (prestoRange.isAll()) {
accumuloRange = new Range();
}
else if (prestoRange.isSingleValue()) {
Text split = new Text(serializer.encode(prestoRange.getType(), prestoRange.getSingleValue()));
accumuloRange = new Range(split);
}
else {
if (prestoRange.getLow().isLowerUnbounded()) {
// If low is unbounded, then create a range from (-inf, value), checking inclusivity
boolean inclusive = prestoRange.getHigh().getBound() == Bound.EXACTLY;
Text split = new Text(serializer.encode(prestoRange.getType(), prestoRange.getHigh().getValue()));
accumuloRange = new Range(null, false, split, inclusive);
}
else if (prestoRange.getHigh().isUpperUnbounded()) {
// If high is unbounded, then create a range from (value, +inf), checking inclusivity
boolean inclusive = prestoRange.getLow().getBound() == Bound.EXACTLY;
Text split = new Text(serializer.encode(prestoRange.getType(), prestoRange.getLow().getValue()));
accumuloRange = new Range(split, inclusive, null, false);
}
else {
// If high is unbounded, then create a range from low to high, checking inclusivity
boolean startKeyInclusive = prestoRange.getLow().getBound() == Bound.EXACTLY;
Text startSplit = new Text(serializer.encode(prestoRange.getType(), prestoRange.getLow().getValue()));
boolean endKeyInclusive = prestoRange.getHigh().getBound() == Bound.EXACTLY;
Text endSplit = new Text(serializer.encode(prestoRange.getType(), prestoRange.getHigh().getValue()));
accumuloRange = new Range(startSplit, startKeyInclusive, endSplit, endKeyInclusive);
}
}
return accumuloRange;
}
}