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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.cassandra.db.filter;
import java.io.IOException;
import java.util.*;
import javax.annotation.Nullable;
import com.google.common.collect.SortedSetMultimap;
import com.google.common.collect.TreeMultimap;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.cassandra.cql3.ColumnIdentifier;
import org.apache.cassandra.db.*;
import org.apache.cassandra.db.rows.CellPath;
import org.apache.cassandra.gms.Gossiper;
import org.apache.cassandra.io.util.DataInputPlus;
import org.apache.cassandra.io.util.DataOutputPlus;
import org.apache.cassandra.net.MessagingService;
import org.apache.cassandra.schema.ColumnMetadata;
import org.apache.cassandra.schema.TableMetadata;
import org.apache.cassandra.utils.CassandraVersion;
/**
* Represents which (non-PK) columns (and optionally which sub-part of a column for complex columns) are selected
* by a query.
*
* We distinguish 2 sets of columns in practice: the _fetched_ columns, which are the columns that we (may, see
* below) need to fetch internally, and the _queried_ columns, which are the columns that the user has selected
* in its request.
*
* The reason for distinguishing those 2 sets is that due to the CQL semantic (see #6588 for more details), we
* often need to internally fetch all regular columns or all columns for the queried table, but can still do some
* optimizations for those columns that are not directly queried by the user (see #10657 for more details).
*
* Note that in practice:
* - the _queried_ columns set is always included in the _fetched_ one.
* - whenever those sets are different, the _fetched_ columns can contain either all the regular columns and
* the static columns queried by the user or all the regular and static columns. If the query is a partition level
* query (no restrictions on clustering or regular columns) all the static columns will need to be fetched as
* some data will need to be returned to the user if the partition has no row but some static data. For all the
* other scenarios only the regular columns are required.
* - in the special case of a {@code SELECT *} query, we want to query all columns, and _fetched_ == _queried.
* As this is a common case, we special case it by using a specific subclass for it.
*
* For complex columns, this class optionally allows to specify a subset of the cells to query for each column.
* We can either select individual cells by path name, or a slice of them. Note that this is a sub-selection of
* _queried_ cells, so if _fetched_ != _queried_, then the cell selected by this sub-selection are considered
* queried and the other ones are considered fetched (and if a column has some sub-selection, it must be a queried
* column, which is actually enforced by the Builder below).
*/
public abstract class ColumnFilter
{
private final static Logger logger = LoggerFactory.getLogger(ColumnFilter.class);
public static final ColumnFilter NONE = selection(RegularAndStaticColumns.NONE);
public static final Serializer serializer = new Serializer();
/**
* The fetching strategy for the different queries.
*/
private enum FetchingStrategy
{
/**
* This strategy will fetch all the regular and static columns.
*
* According to the CQL semantic a partition exists if it has at least one row or one of its static columns is not null.
* For queries that have no restrictions on the clustering or regular columns, C* will return some data for
* the partition even if it does not contains any row as long as one of the static columns contains data.
* To be able to ensure those queries all columns need to be fetched.
*
* This strategy is also used, instead of the ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS one, in mixed version clusters
* where some nodes have a version lower than 4.0. To ensure backward compatibility with those version that interpret the
* _fetchAll_ serialization flag as a true fetch all request.
*/
ALL_COLUMNS
{
@Override
boolean fetchesAllColumns(boolean isStatic)
{
return true;
}
@Override
RegularAndStaticColumns getFetchedColumns(TableMetadata metadata, RegularAndStaticColumns queried)
{
return metadata.regularAndStaticColumns();
}
},
/**
* This strategy will fetch all the regular and selected static columns.
*
* According to the CQL semantic a row exists if at least one of its columns is not null.
* To ensure that we need to fetch all regular columns.
*/
ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS
{
@Override
boolean fetchesAllColumns(boolean isStatic)
{
return !isStatic;
}
@Override
RegularAndStaticColumns getFetchedColumns(TableMetadata metadata, RegularAndStaticColumns queried)
{
return new RegularAndStaticColumns(queried.statics, metadata.regularColumns());
}
},
/**
* Fetch only the columns that have been selected.
*
* With this strategy _queried_ == _fetched_. This strategy is only used for internal queries.
*/
ONLY_QUERIED_COLUMNS
{
@Override
boolean fetchesAllColumns(boolean isStatic)
{
return false;
}
@Override
boolean areAllFetchedColumnsQueried()
{
return true;
}
@Override
RegularAndStaticColumns getFetchedColumns(TableMetadata metadata, RegularAndStaticColumns queried)
{
return queried;
}
};
/**
* Checks if the strategy fetch all the specified columns
*
* @param isStatic {@code true} is the check is for static columns, {@code false} otherwise
* @return {@code true} if the strategy fetch all the static columns, {@code false} otherwise.
*/
abstract boolean fetchesAllColumns(boolean isStatic);
/**
* Checks if all the fetched columns are guaranteed to be queried
*
* @return {@code true} if all the fetched columns are guaranteed to be queried, {@code false} otherwise.
*/
boolean areAllFetchedColumnsQueried()
{
return false;
}
/**
* Returns the columns that must be fetched to answer the query.
*
* @param metadata the table metadata
* @param queried the queried columns
* @return the columns that must be fetched
*/
abstract RegularAndStaticColumns getFetchedColumns(TableMetadata metadata, RegularAndStaticColumns queried);
}
/**
* Returns {@code true} if there are pre-4.0-rc2 nodes in the cluster, {@code false} otherwise.
*
* ColumnFilters from 4.0 releases before RC2 wrongly assumed that fetching all regular columns and not
* the static columns was enough. That was not the case for queries that needed to return rows for empty partitions.
* See CASSANDRA-16686 for more details.
*/
private static boolean isUpgradingFromVersionLowerThan40RC2()
{
if (Gossiper.instance.isUpgradingFromVersionLowerThan(CassandraVersion.CASSANDRA_4_0_RC2))
{
logger.trace("ColumnFilter conversion has been applied so that static columns will not be fetched because there are pre 4.0-rc2 nodes in the cluster");
return true;
}
return false;
}
/**
* Returns {@code true} if there are pre-4.0 nodes in the cluster, {@code false} otherwise.
*
* If there pre-4.0 nodes in the cluster all static columns should be fetched along with all regular columns.
* This is due to the fact that this nodes have a different understanding of the fetchAll serialization flag.
* Pre-4.0 the fetchAll flag meant that all the columns regular AND STATIC should be fetched whereas for 4.0
* nodes it meant that only the regular columns and the queried static columns should be fetched.
*/
private static boolean isUpgradingFromVersionLowerThan40()
{
if (Gossiper.instance.isUpgradingFromVersionLowerThan(CassandraVersion.CASSANDRA_4_0))
{
logger.trace("ColumnFilter conversion has been applied so that all static columns will be fetched because there are pre 4.0 nodes in the cluster");
return true;
}
return false;
}
/**
* Returns {@code true} if there are pre-3.4 nodes in the cluster, {@code false} otherwise.
*
* When fetchAll is enabled on pre CASSANDRA-10657 (3.4-), queried columns are not considered at all, and it
* is assumed that all columns are queried. CASSANDRA-10657 (3.4+) brings back skipping values of columns
* which are not in queried set when fetchAll is enabled. That makes exactly the same filter being
* interpreted in a different way on 3.4- and 3.4+.
*
* Moreover, there is no way to convert the filter with fetchAll and queried != null so that it is
* interpreted the same way on 3.4- because that Cassandra version does not support such filtering.
*
* In order to avoid inconsistencies in data read by 3.4- and 3.4+ we need to avoid creation of incompatible
* filters when the cluster contains 3.4- nodes. We need to do that by using a wildcard query.
*
* see CASSANDRA-10657, CASSANDRA-15833, CASSANDRA-16415
*/
private static boolean isUpgradingFromVersionLowerThan34()
{
if (Gossiper.instance.isUpgradingFromVersionLowerThan(CassandraVersion.CASSANDRA_3_4))
{
logger.trace("ColumnFilter conversion has been applied so that all columns will be queried because there are pre 3.4 nodes in the cluster");
return true;
}
return false;
}
/**
* A filter that includes all columns for the provided table.
*/
public static ColumnFilter all(TableMetadata metadata)
{
return new WildCardColumnFilter(metadata.regularAndStaticColumns());
}
/**
* A filter that only fetches/queries the provided columns.
*
* Note that this shouldn't be used for CQL queries in general as all columns should be queried to
* preserve CQL semantic (see class javadoc). This is ok for some internal queries however (and
* for #6588 if/when we implement it).
*/
public static ColumnFilter selection(RegularAndStaticColumns columns)
{
return SelectionColumnFilter.newInstance(FetchingStrategy.ONLY_QUERIED_COLUMNS, null, columns, null);
}
/**
* A filter that fetches all columns for the provided table, but returns
* only the queried ones.
*/
public static ColumnFilter selection(TableMetadata metadata,
RegularAndStaticColumns queried,
boolean returnStaticContentOnPartitionWithNoRows)
{
// pre CASSANDRA-10657 (3.4-), when fetchAll is enabled, queried columns are not considered at all, and it
// is assumed that all columns are queried.
if (isUpgradingFromVersionLowerThan34())
{
return new WildCardColumnFilter(metadata.regularAndStaticColumns());
}
// pre CASSANDRA-12768 (4.0-) all static columns should be fetched along with all regular columns.
if (isUpgradingFromVersionLowerThan40())
{
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_COLUMNS, metadata, queried, null);
}
// pre CASSANDRA-16686 (4.0-RC2-) static columns were not fetched unless queried which led to some wrong
// results for some queries
if (!returnStaticContentOnPartitionWithNoRows || isUpgradingFromVersionLowerThan40RC2())
{
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS, metadata, queried, null);
}
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_COLUMNS, metadata, queried, null);
}
/**
* The columns that needs to be fetched internally for this filter.
*
* @return the columns to fetch for this filter.
*/
public abstract RegularAndStaticColumns fetchedColumns();
/**
* The columns actually queried by the user.
*
* Note that this is in general not all the columns that are fetched internally (see {@link #fetchedColumns}).
*/
public abstract RegularAndStaticColumns queriedColumns();
/**
* Whether all the (regular or static) columns are fetched by this filter.
*
* Note that this method is meant as an optimization but a negative return
* shouldn't be relied upon strongly: this can return {@code false} but
* still have all the columns fetches if those were manually selected by the
* user. The goal here is to cheaply avoid filtering things on wildcard
* queries, as those are common.
*
* @param isStatic whether to check for static columns or not. If {@code true},
* the method returns if all static columns are fetched, otherwise it checks
* regular columns.
*/
public abstract boolean fetchesAllColumns(boolean isStatic);
/**
* Whether _fetched_ == _queried_ for this filter, and so if the {@code isQueried()} methods
* can return {@code false} for some column/cell.
*/
public abstract boolean allFetchedColumnsAreQueried();
/**
* Whether the provided column is fetched by this filter.
*/
public abstract boolean fetches(ColumnMetadata column);
/**
* Whether the provided column, which is assumed to be _fetched_ by this filter (so the caller must guarantee
* that {@code fetches(column) == true}, is also _queried_ by the user.
*
* !WARNING! please be sure to understand the difference between _fetched_ and _queried_
* columns that this class made before using this method. If unsure, you probably want
* to use the {@link #fetches} method.
*/
public abstract boolean fetchedColumnIsQueried(ColumnMetadata column);
/**
* Whether the provided complex cell (identified by its column and path), which is assumed to be _fetched_ by
* this filter, is also _queried_ by the user.
*
* !WARNING! please be sure to understand the difference between _fetched_ and _queried_
* columns that this class made before using this method. If unsure, you probably want
* to use the {@link #fetches} method.
*/
public abstract boolean fetchedCellIsQueried(ColumnMetadata column, CellPath path);
/**
* Creates a new {@code Tester} to efficiently test the inclusion of cells of complex column
* {@code column}.
*
* @param column for complex column for which to create a tester.
* @return the created tester or {@code null} if all the cells from the provided column
* are queried.
*/
@Nullable
public abstract Tester newTester(ColumnMetadata column);
/**
* Checks if this {@code ColumnFilter} is for a wildcard query.
*
* @return {@code true} if this {@code ColumnFilter} is for a wildcard query, {@code false} otherwise.
*/
public boolean isWildcard()
{
return false;
}
/**
* Returns the CQL string corresponding to this {@code ColumnFilter}.
*
* @return the CQL string corresponding to this {@code ColumnFilter}.
*/
public abstract String toCQLString();
/**
* Returns the sub-selections or {@code null} if there are none.
*
* @return the sub-selections or {@code null} if there are none
*/
protected abstract SortedSetMultimap subSelections();
/**
* Returns a {@code ColumnFilter} builder that fetches all regular columns or all columns (and queries the columns
* added to the builder, or everything if no column is added).
*
* @param metadata the table metadata
* @param returnStaticContentOnPartitionWithNoRows {@code true} if the query must return static contents if the partition has no row,
* {@code false} otherwise.
*/
public static Builder allRegularColumnsBuilder(TableMetadata metadata, boolean returnStaticContentOnPartitionWithNoRows)
{
return new Builder(metadata, returnStaticContentOnPartitionWithNoRows);
}
/**
* Returns a {@code ColumnFilter} builder that only fetches the columns/cells added to the builder.
*/
public static Builder selectionBuilder()
{
return new Builder(null, false);
}
public static class Tester
{
private final boolean isFetched;
private ColumnSubselection current;
private final Iterator iterator;
private Tester(boolean isFetched, Iterator iterator)
{
this.isFetched = isFetched;
this.iterator = iterator;
}
public boolean fetches(CellPath path)
{
return isFetched || hasSubselection(path);
}
/**
* Must only be called if {@code fetches(path) == true}.
*/
public boolean fetchedCellIsQueried(CellPath path)
{
return !isFetched || hasSubselection(path);
}
private boolean hasSubselection(CellPath path)
{
while (current != null || iterator.hasNext())
{
if (current == null)
current = iterator.next();
int cmp = current.compareInclusionOf(path);
if (cmp == 0) // The path is included
return true;
else if (cmp < 0) // The path is before this sub-selection, it's not included by any
return false;
// the path is after this sub-selection, we need to check the next one.
current = null;
}
return false;
}
}
/**
* A builder for a {@code ColumnFilter} object.
*
* Note that the columns added to this build are the _queried_ column. Whether or not all columns
* are _fetched_ depends on which constructor you've used to obtained this builder, allRegularColumnsBuilder (all
* columns are fetched) or selectionBuilder (only the queried columns are fetched).
*
* Note that for a allRegularColumnsBuilder, if no queried columns are added, this is interpreted as querying
* all columns, not querying none (but if you know you want to query all columns, prefer
* {@link ColumnFilter#all(TableMetadata)}. For selectionBuilder, adding no queried columns means no column will be
* fetched (so the builder will return {@code PartitionColumns.NONE}).
*
* Also, if only a sub-selection of a complex column should be queried, then only the corresponding
* sub-selection method of the builder ({@link #slice} or {@link #select}) should be called for the
* column, but {@link #add} shouldn't. if {@link #add} is also called, the whole column will be
* queried and the sub-selection(s) will be ignored. This is done for correctness of CQL where
* if you do "SELECT m, m[2..5]", you are really querying the whole collection.
*/
public static class Builder
{
private final TableMetadata metadata; // null if we don't fetch all columns
/**
* {@code true} if the query must return static contents if the partition has no row, {@code false} otherwise.
*/
private final boolean returnStaticContentOnPartitionWithNoRows;
private RegularAndStaticColumns.Builder queriedBuilder;
private List subSelections;
private Set fullySelectedComplexColumns;
private Builder(TableMetadata metadata, boolean returnStaticContentOnPartitionWithNoRows)
{
this.metadata = metadata;
this.returnStaticContentOnPartitionWithNoRows = returnStaticContentOnPartitionWithNoRows;
}
public Builder add(ColumnMetadata c)
{
if (c.isComplex() && c.type.isMultiCell())
{
if (fullySelectedComplexColumns == null)
fullySelectedComplexColumns = new HashSet<>();
fullySelectedComplexColumns.add(c);
}
return addInternal(c);
}
public Builder addAll(Iterable columns)
{
for (ColumnMetadata column : columns)
add(column);
return this;
}
private Builder addInternal(ColumnMetadata c)
{
if (c.isPrimaryKeyColumn())
return this;
if (queriedBuilder == null)
queriedBuilder = RegularAndStaticColumns.builder();
queriedBuilder.add(c);
return this;
}
private Builder addSubSelection(ColumnSubselection subSelection)
{
ColumnMetadata column = subSelection.column();
assert column.isComplex() && column.type.isMultiCell();
addInternal(column);
if (subSelections == null)
subSelections = new ArrayList<>();
subSelections.add(subSelection);
return this;
}
public Builder slice(ColumnMetadata c, CellPath from, CellPath to)
{
return addSubSelection(ColumnSubselection.slice(c, from, to));
}
public Builder select(ColumnMetadata c, CellPath elt)
{
return addSubSelection(ColumnSubselection.element(c, elt));
}
public ColumnFilter build()
{
boolean isFetchAll = metadata != null;
RegularAndStaticColumns queried = queriedBuilder == null ? null : queriedBuilder.build();
// It's only ok to have queried == null in ColumnFilter if isFetchAll. So deal with the case of a selectionBuilder
// with nothing selected (we can at least happen on some backward compatible queries - CASSANDRA-10471).
if (!isFetchAll && queried == null)
queried = RegularAndStaticColumns.NONE;
SortedSetMultimap s = buildSubSelections();
if (isFetchAll)
{
// When fetchAll is enabled on pre CASSANDRA-10657 (3.4-), queried columns are not considered at all, and it
// is assumed that all columns are queried. CASSANDRA-10657 (3.4+) brings back skipping values of columns
// which are not in queried set when fetchAll is enabled. That makes exactly the same filter being
// interpreted in a different way on 3.4- and 3.4+.
//
// Moreover, there is no way to convert the filter with fetchAll and queried != null so that it is
// interpreted the same way on 3.4- because that Cassandra version does not support such filtering.
//
// In order to avoid inconsitencies in data read by 3.4- and 3.4+ we need to avoid creation of incompatible
// filters when the cluster contains 3.4- nodes. We do that by forcibly setting queried to null.
//
// see CASSANDRA-10657, CASSANDRA-15833, CASSANDRA-16415
if (queried == null || isUpgradingFromVersionLowerThan34())
{
return new WildCardColumnFilter(metadata.regularAndStaticColumns());
}
// pre CASSANDRA-12768 (4.0-) all static columns should be fetched along with all regular columns.
if (isUpgradingFromVersionLowerThan40())
{
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_COLUMNS, metadata, queried, s);
}
// pre CASSANDRA-16686 (4.0-RC2-) static columns where not fetched unless queried witch lead to some wrong results
// for some queries
if (!returnStaticContentOnPartitionWithNoRows || isUpgradingFromVersionLowerThan40RC2())
{
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS, metadata, queried, s);
}
return SelectionColumnFilter.newInstance(FetchingStrategy.ALL_COLUMNS, metadata, queried, s);
}
return SelectionColumnFilter.newInstance(FetchingStrategy.ONLY_QUERIED_COLUMNS, (TableMetadata) null, queried, s);
}
private SortedSetMultimap buildSubSelections()
{
if (subSelections == null)
return null;
SortedSetMultimap s = TreeMultimap.create(Comparator.naturalOrder(), Comparator.naturalOrder());
for (ColumnSubselection subSelection : subSelections)
{
if (fullySelectedComplexColumns == null || !fullySelectedComplexColumns.contains(subSelection.column()))
s.put(subSelection.column().name, subSelection);
}
return s;
}
}
/**
* {@code ColumnFilter} sub-class for wildcard queries.
*
* The class does not rely on TableMetadata and expects a fix set of columns to prevent issues
* with Schema race propagation. See CASSANDRA-15899.
*/
public static class WildCardColumnFilter extends ColumnFilter
{
/**
* The queried and fetched columns.
*/
private final RegularAndStaticColumns fetchedAndQueried;
/**
* Creates a {@code ColumnFilter} for wildcard queries.
*
* The class does not rely on TableMetadata and expects a fix set of columns to prevent issues
* with Schema race propagation. See CASSANDRA-15899.
*
* @param fetchedAndQueried the fetched and queried columns
*/
private WildCardColumnFilter(RegularAndStaticColumns fetchedAndQueried)
{
this.fetchedAndQueried = fetchedAndQueried;
}
@Override
public RegularAndStaticColumns fetchedColumns()
{
return fetchedAndQueried;
}
@Override
public RegularAndStaticColumns queriedColumns()
{
return fetchedAndQueried;
}
@Override
public boolean fetchesAllColumns(boolean isStatic)
{
return true;
}
@Override
public boolean allFetchedColumnsAreQueried()
{
return true;
}
@Override
public boolean fetches(ColumnMetadata column)
{
return true;
}
@Override
public boolean fetchedColumnIsQueried(ColumnMetadata column)
{
return true;
}
@Override
public boolean fetchedCellIsQueried(ColumnMetadata column, CellPath path)
{
return true;
}
@Override
public Tester newTester(ColumnMetadata column)
{
return null;
}
@Override
public boolean equals(Object other)
{
if (other == this)
return true;
if (!(other instanceof WildCardColumnFilter))
return false;
WildCardColumnFilter w = (WildCardColumnFilter) other;
return fetchedAndQueried.equals(w.fetchedAndQueried);
}
@Override
public int hashCode()
{
return Objects.hash(fetchedAndQueried);
}
@Override
public String toString()
{
return "*/*";
}
public String toCQLString()
{
return "*";
}
@Override
public boolean isWildcard()
{
return true;
}
@Override
protected SortedSetMultimap subSelections()
{
return null;
}
}
/**
* {@code ColumnFilter} sub-class for queries with selected columns.
*
* The class does not rely on TableMetadata and expect a fix set of fetched columns to prevent issues
* with Schema race propagation. See CASSANDRA-15899.
*/
public static class SelectionColumnFilter extends ColumnFilter
{
public final FetchingStrategy fetchingStrategy;
/**
* The selected columns
*/
private final RegularAndStaticColumns queried;
/**
* The columns that need to be fetched to be able
*/
private final RegularAndStaticColumns fetched;
private final SortedSetMultimap subSelections; // can be null
public static SelectionColumnFilter newInstance(FetchingStrategy fetchingStrategy,
TableMetadata metadata,
RegularAndStaticColumns queried,
SortedSetMultimap subSelections)
{
assert fetchingStrategy != FetchingStrategy.ONLY_QUERIED_COLUMNS || metadata == null;
assert queried != null;
return new SelectionColumnFilter(fetchingStrategy,
queried,
fetchingStrategy.getFetchedColumns(metadata, queried),
subSelections);
}
/**
* Creates a {@code ColumnFilter} for queries with selected columns.
*
* The class does not rely on TableMetadata and expect a fix set of columns to prevent issues
* with Schema race propagation. See CASSANDRA-15899.
*
* @param fetchingStrategy the strategy used to select the fetched columns
* @param fetched the columns that must be fetched
* @param queried the queried columns
* @param subSelections the columns sub-selections
*/
public SelectionColumnFilter(FetchingStrategy fetchingStrategy,
RegularAndStaticColumns queried,
RegularAndStaticColumns fetched,
SortedSetMultimap subSelections)
{
assert queried != null;
assert fetched.includes(queried);
this.fetchingStrategy = fetchingStrategy;
this.queried = queried;
this.fetched = fetched;
this.subSelections = subSelections;
}
@Override
public RegularAndStaticColumns fetchedColumns()
{
return fetched;
}
@Override
public RegularAndStaticColumns queriedColumns()
{
return queried;
}
@Override
public boolean fetchesAllColumns(boolean isStatic)
{
return fetchingStrategy.fetchesAllColumns(isStatic);
}
@Override
public boolean allFetchedColumnsAreQueried()
{
return fetchingStrategy.areAllFetchedColumnsQueried();
}
@Override
public boolean fetches(ColumnMetadata column)
{
return fetchingStrategy.fetchesAllColumns(column.isStatic()) || fetched.contains(column);
}
/**
* Whether the provided complex cell (identified by its column and path), which is assumed to be _fetched_ by
* this filter, is also _queried_ by the user.
*
* !WARNING! please be sure to understand the difference between _fetched_ and _queried_
* columns that this class made before using this method. If unsure, you probably want
* to use the {@link #fetches} method.
*/
@Override
public boolean fetchedColumnIsQueried(ColumnMetadata column)
{
return fetchingStrategy.areAllFetchedColumnsQueried() || queried.contains(column);
}
@Override
public boolean fetchedCellIsQueried(ColumnMetadata column, CellPath path)
{
assert path != null;
// first verify that the column to which the cell belongs is queried
if (!fetchedColumnIsQueried(column))
return false;
if (subSelections == null)
return true;
SortedSet s = subSelections.get(column.name);
// No subsection for this column means everything is queried
if (s.isEmpty())
return true;
for (ColumnSubselection subSel : s)
if (subSel.compareInclusionOf(path) == 0)
return true;
return false;
}
@Override
public Tester newTester(ColumnMetadata column)
{
if (subSelections == null || !column.isComplex())
return null;
SortedSet s = subSelections.get(column.name);
if (s.isEmpty())
return null;
return new Tester(fetchingStrategy.fetchesAllColumns(column.isStatic()), s.iterator());
}
@Override
protected SortedSetMultimap subSelections()
{
return subSelections;
}
@Override
public boolean equals(Object other)
{
if (other == this)
return true;
if (!(other instanceof SelectionColumnFilter))
return false;
SelectionColumnFilter otherCf = (SelectionColumnFilter) other;
return otherCf.fetchingStrategy == this.fetchingStrategy &&
Objects.equals(otherCf.queried, this.queried) &&
Objects.equals(otherCf.fetched, this.fetched) &&
Objects.equals(otherCf.subSelections, this.subSelections);
}
@Override
public int hashCode()
{
return Objects.hash(fetchingStrategy, queried, fetched, subSelections);
}
@Override
public String toString()
{
String prefix = "";
if (fetchingStrategy.fetchesAllColumns(true))
prefix = "*/";
if (fetchingStrategy == FetchingStrategy.ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS)
{
prefix = queried.statics.isEmpty()
? "/"
: String.format("+%s/", toString(queried.statics.selectOrderIterator(), false));
}
return prefix + toString(queried.selectOrderIterator(), false);
}
@Override
public String toCQLString()
{
return queried.isEmpty() ? "*" : toString(queried.selectOrderIterator(), true);
}
private String toString(Iterator columns, boolean cql)
{
StringJoiner joiner = cql ? new StringJoiner(", ") : new StringJoiner(", ", "[", "]");
while (columns.hasNext())
{
ColumnMetadata column = columns.next();
String columnName = cql ? column.name.toCQLString() : String.valueOf(column.name);
SortedSet s = subSelections != null
? subSelections.get(column.name)
: Collections.emptySortedSet();
if (s.isEmpty())
joiner.add(columnName);
else
s.forEach(subSel -> joiner.add(String.format("%s%s", columnName, subSel)));
}
return joiner.toString();
}
}
public static class Serializer
{
// Prior to 4.0 the FETCH_ALL flag meant fetch all regular and static columns. From 4.0 onward it meant
// fetch all regular columns and queried static columns
private static final int FETCH_ALL_MASK = 0x01;
private static final int HAS_QUERIED_MASK = 0x02;
private static final int HAS_SUB_SELECTIONS_MASK = 0x04;
// The FETCH_ALL_STATICS flag was added in CASSANDRA-16686 to allow 4.0 to handle queries that required
// to return static data for empty partitions
private static final int FETCH_ALL_STATICS_MASK = 0x08;
private static int makeHeaderByte(ColumnFilter selection)
{
return (selection.fetchesAllColumns(false) ? FETCH_ALL_MASK : 0)
| (!selection.isWildcard() ? HAS_QUERIED_MASK : 0)
| (selection.subSelections() != null ? HAS_SUB_SELECTIONS_MASK : 0)
| (selection.fetchesAllColumns(true) ? FETCH_ALL_STATICS_MASK : 0);
}
public void serialize(ColumnFilter selection, DataOutputPlus out, int version) throws IOException
{
out.writeByte(makeHeaderByte(selection));
if (version >= MessagingService.VERSION_3014 && selection.fetchesAllColumns(false))
{
serializeRegularAndStaticColumns(selection.fetchedColumns(), out);
}
if (!selection.isWildcard())
{
serializeRegularAndStaticColumns(selection.queriedColumns(), out);
}
serializeSubSelections(selection.subSelections(), out, version);
}
private void serializeSubSelections(SortedSetMultimap subSelections,
DataOutputPlus out,
int version) throws IOException
{
if (subSelections != null)
{
out.writeUnsignedVInt(subSelections.size());
for (ColumnSubselection subSel : subSelections.values())
ColumnSubselection.serializer.serialize(subSel, out, version);
}
}
private void serializeRegularAndStaticColumns(RegularAndStaticColumns regularAndStaticColumns,
DataOutputPlus out) throws IOException
{
Columns.serializer.serialize(regularAndStaticColumns.statics, out);
Columns.serializer.serialize(regularAndStaticColumns.regulars, out);
}
public ColumnFilter deserialize(DataInputPlus in, int version, TableMetadata metadata) throws IOException
{
int header = in.readUnsignedByte();
// The meaning of isFetchAll is actually different for pre-4.0 versions and for 4.0+ versions
// In 4.0+ it meant is fetch all regulars
boolean isFetchAll = (header & FETCH_ALL_MASK) != 0;
boolean hasQueried = (header & HAS_QUERIED_MASK) != 0;
boolean hasSubSelections = (header & HAS_SUB_SELECTIONS_MASK) != 0;
boolean isFetchAllStatics = (header & FETCH_ALL_STATICS_MASK) != 0;
RegularAndStaticColumns fetched = null;
RegularAndStaticColumns queried = null;
if (isFetchAll)
{
if (version >= MessagingService.VERSION_3014)
{
fetched = deserializeRegularAndStaticColumns(in, metadata);
}
else
{
fetched = metadata.regularAndStaticColumns();
}
}
if (hasQueried)
{
queried = deserializeRegularAndStaticColumns(in, metadata);
}
SortedSetMultimap subSelections = null;
if (hasSubSelections)
{
subSelections = deserializeSubSelection(in, version, metadata);
}
if (isFetchAll)
{
// pre CASSANDRA-10657 (3.4-), when fetchAll is enabled, queried columns are not considered at all, and it
// is assumed that all columns are queried.
if (!hasQueried || isUpgradingFromVersionLowerThan34())
{
return new WildCardColumnFilter(fetched);
}
// pre CASSANDRA-12768 (4.0-) all static columns should be fetched along with all regular columns.
if (isUpgradingFromVersionLowerThan40())
{
return new SelectionColumnFilter(FetchingStrategy.ALL_COLUMNS, queried, fetched, subSelections);
}
// pre CASSANDRA-16686 (4.0-RC2-) static columns where not fetched unless queried witch lead to some wrong results
// for some queries
if (!isFetchAllStatics || isUpgradingFromVersionLowerThan40RC2())
{
return new SelectionColumnFilter(FetchingStrategy.ALL_REGULARS_AND_QUERIED_STATICS_COLUMNS, queried, fetched, subSelections);
}
return new SelectionColumnFilter(FetchingStrategy.ALL_COLUMNS, queried, fetched, subSelections);
}
return new SelectionColumnFilter(FetchingStrategy.ONLY_QUERIED_COLUMNS, queried, queried, subSelections);
}
private RegularAndStaticColumns deserializeRegularAndStaticColumns(DataInputPlus in,
TableMetadata metadata) throws IOException
{
Columns statics = Columns.serializer.deserialize(in, metadata);
Columns regulars = Columns.serializer.deserialize(in, metadata);
return new RegularAndStaticColumns(statics, regulars);
}
private SortedSetMultimap deserializeSubSelection(DataInputPlus in,
int version,
TableMetadata metadata) throws IOException
{
SortedSetMultimap subSelections = TreeMultimap.create(Comparator.naturalOrder(), Comparator.naturalOrder());
int size = (int) in.readUnsignedVInt();
for (int i = 0; i < size; i++)
{
ColumnSubselection subSel = ColumnSubselection.serializer.deserialize(in, version, metadata);
subSelections.put(subSel.column().name, subSel);
}
return subSelections;
}
public long serializedSize(ColumnFilter selection, int version)
{
long size = 1; // header byte
if (version >= MessagingService.VERSION_3014 && selection.fetchesAllColumns(false))
{
size += regularAndStaticColumnsSerializedSize(selection.fetchedColumns());
}
if (!selection.isWildcard())
{
size += regularAndStaticColumnsSerializedSize(selection.queriedColumns());
}
size += subSelectionsSerializedSize(selection.subSelections(), version);
return size;
}
private long regularAndStaticColumnsSerializedSize(RegularAndStaticColumns columns)
{
return Columns.serializer.serializedSize(columns.statics)
+ Columns.serializer.serializedSize(columns.regulars);
}
private long subSelectionsSerializedSize(SortedSetMultimap subSelections,
int version)
{
if (subSelections == null)
return 0;
int size = TypeSizes.sizeofUnsignedVInt(subSelections.size());
for (ColumnSubselection subSel : subSelections.values())
size += ColumnSubselection.serializer.serializedSize(subSel, version);
return size;
}
}
}