Package org.apache.ignite.cache.query

Class SqlFieldsQuery

  • All Implemented Interfaces:
    Serializable
    public class SqlFieldsQuery
extends Query<List<?>>
    SQL Fields query. This query can return specific fields of data based on SQL 'select' clause.

    Collocated Flag

    Collocation flag is used for optimization purposes. Whenever Ignite executes a distributed query, it sends sub-queries to individual cluster members. If you know in advance that the elements of your query selection are collocated together on the same node, usually based on some affinity-key, Ignite can make significant performance and network optimizations.

    For example, in case of Word-Count example, we know that all identical words are processed on the same cluster member, because we use the word itself as affinity key. This allows Ignite to execute the 'limit' clause on the remote nodes and bring back only the small data set specified within the 'limit' clause, instead of the whole query result as would happen in a non-collocated execution.

    See Also:
    IgniteCache.query(Query), Serialized Form

    • Field Detail

      • DFLT_LAZY

        public static boolean DFLT_LAZY
        Do not remove. For tests only.

    • Constructor Detail

      • SqlFieldsQuery

        public SqlFieldsQuery​(SqlFieldsQuery qry)
        Copy constructs SQL fields query.
        Parameters:
        qry - SQL query.

      • SqlFieldsQuery

        public SqlFieldsQuery​(String sql)
        Constructs SQL fields query.
        Parameters:
        sql - SQL query.

      • SqlFieldsQuery

        public SqlFieldsQuery​(String sql,
                      boolean collocated)
        Constructs SQL fields query.
        Parameters:
        sql - SQL query.
        collocated - Collocated flag.

    • Method Detail

      • getSql

        public String getSql()
        Gets SQL clause.
        Returns:
        SQL clause.

      • setSql

        public SqlFieldsQuery setSql​(String sql)
        Sets SQL clause.
        Parameters:
        sql - SQL clause.
        Returns:
        this For chaining.

      • getArgs

        public Object[] getArgs()
        Gets SQL arguments.
        Returns:
        SQL arguments.

      • setArgs

        public SqlFieldsQuery setArgs​(Object... args)
        Sets SQL arguments.
        Parameters:
        args - SQL arguments.
        Returns:
        this For chaining.

      • getTimeout

        public int getTimeout()
        Gets the query execution timeout in milliseconds.
        Returns:
        Timeout value.

      • setTimeout

        public SqlFieldsQuery setTimeout​(int timeout,
                                 TimeUnit timeUnit)
        Sets the query execution timeout. Query will be automatically cancelled if the execution timeout is exceeded.
        Parameters:
        timeout - Timeout value. Zero value disables timeout.
        timeUnit - Time unit.
        Returns:
        this For chaining.

      • isCollocated

        public boolean isCollocated()
        Checks if this query is collocated.
        Returns:
        true If the query is collocated.

      • setCollocated

        public SqlFieldsQuery setCollocated​(boolean collocated)
        Sets flag defining if this query is collocated. Collocation flag is used for optimization purposes of queries with GROUP BY statements. Whenever Ignite executes a distributed query, it sends sub-queries to individual cluster members. If you know in advance that the elements of your query selection are collocated together on the same node and you group by collocated key (primary or affinity key), then Ignite can make significant performance and network optimizations by grouping data on remote nodes.
        Parameters:
        collocated - Flag value.
        Returns:
        this For chaining.

      • isEnforceJoinOrder

        public boolean isEnforceJoinOrder()
        Checks if join order of tables if enforced.
        Returns:
        Flag value.

      • setEnforceJoinOrder

        public SqlFieldsQuery setEnforceJoinOrder​(boolean enforceJoinOrder)
        Sets flag to enforce join order of tables in the query. If set to true query optimizer will not reorder tables in join. By default is false.

        It is not recommended to enable this property until you are sure that your indexes and the query itself are correct and tuned as much as possible but query optimizer still produces wrong join order.

        Parameters:
        enforceJoinOrder - Flag value.
        Returns:
        this For chaining.

      • setDistributedJoins

        public SqlFieldsQuery setDistributedJoins​(boolean distributedJoins)
        Specify if distributed joins are enabled for this query.
        Parameters:
        distributedJoins - Distributed joins enabled.
        Returns:
        this For chaining.

      • isDistributedJoins

        public boolean isDistributedJoins()
        Check if distributed joins are enabled for this query.
        Returns:
        true If distributed joins enabled.

      • setPageSize

        public SqlFieldsQuery setPageSize​(int pageSize)
        Sets optional page size, if 0, then default is used.
        Overrides:
        setPageSize in class Query<List<?>>
        Parameters:
        pageSize - Optional page size.
        Returns:
        this for chaining.

      • setLocal

        public SqlFieldsQuery setLocal​(boolean loc)
        Sets whether this query should be executed on local node only.
        Overrides:
        setLocal in class Query<List<?>>
        Parameters:
        loc - Local flag.
        Returns:
        this for chaining.

      • setReplicatedOnly

        @Deprecated
public SqlFieldsQuery setReplicatedOnly​(boolean replicatedOnly)
        Deprecated.
        No longer used as of Apache Ignite 2.8.
        Specify if the query contains only replicated tables. This is a hint for potentially more effective execution.
        Parameters:
        replicatedOnly - The query contains only replicated tables.
        Returns:
        this For chaining.

      • isReplicatedOnly

        @Deprecated
public boolean isReplicatedOnly()
        Deprecated.
        No longer used as of Apache Ignite 2.8.
        Check is the query contains only replicated tables.
        Returns:
        true If the query contains only replicated tables.

      • setLazy

        public SqlFieldsQuery setLazy​(boolean lazy)
        Deprecated.
        Use setPageSize(int) instead.
        Sets lazy query execution flag.

        If lazy=false Ignite will attempt to fetch the whole query result set to memory and send it to the client. For small and medium result sets this provides optimal performance and minimize duration of internal database locks, thus increasing concurrency.

        If result set is too big to fit in available memory this could lead to excessive GC pauses and even OutOfMemoryError. Use this flag as a hint for Ignite to fetch result set lazily, thus minimizing memory consumption at the cost of moderate performance hit.

        Defaults to true, meaning that the only first page of result set is fetched to memory.

        Parameters:
        lazy - Lazy query execution flag.
        Returns:
        this For chaining.

      • getPartitions

        @Nullable
public @org.jetbrains.annotations.Nullable int[] getPartitions()
        Returns:
        Partitions for query, in ascending order.

      • setPartitions

        public SqlFieldsQuery setPartitions​(@Nullable
                                    @org.jetbrains.annotations.Nullable int... parts)
        Sets partitions for a query. The query will be executed only on nodes which are primary for specified partitions.

        Note what passed array'll be sorted in place for performance reasons, if it wasn't sorted yet.

        Parameters:
        parts - Partitions.
        Returns:
        this for chaining.

      • getSchema

        @Nullable
public @Nullable String getSchema()
        Get schema for the query. If not set, current cache name is used, which means you can omit schema name for tables within the current cache.
        Returns:
        Schema. Null if schema is not set.

      • setSchema

        public SqlFieldsQuery setSchema​(@Nullable
                                @Nullable String schema)
        Set schema for the query. If not set, current cache name is used, which means you can omit schema name for tables within the current cache.
        Parameters:
        schema - Schema. Null to unset schema.
        Returns:
        this for chaining.

      • getUpdateBatchSize

        public int getUpdateBatchSize()
        Gets update internal bach size. Default is 1 to prevent deadlock on update where keys sequence are different in several concurrent updates.
        Returns:
        Update internal batch size

      • setUpdateBatchSize

        public SqlFieldsQuery setUpdateBatchSize​(int updateBatchSize)
        Sets update internal bach size. Default is 1 to prevent deadlock on update where keys sequence are different in several concurrent updates.
        Parameters:
        updateBatchSize - Update internal batch size.
        Returns:
        this for chaining.

      • getQueryInitiatorId

        public String getQueryInitiatorId()
        Returns:
        Query's initiator identifier string (client host+port, user name, job name or any user's information about query initiator).

      • setQueryInitiatorId

        public SqlFieldsQuery setQueryInitiatorId​(String qryInitiatorId)
        Parameters:
        qryInitiatorId - Query's initiator identifier string (client host+port, user name, job name or any user's information about query initiator).
        Returns:
        this for chaining.

      • setThreadedQueryInitiatorId

        public static void setThreadedQueryInitiatorId​(String originator)
        Used at the Job worker to setup originator by default for current thread.
        Parameters:
        originator - Query's originator string.

      • resetThreadedQueryInitiatorId

        public static void resetThreadedQueryInitiatorId()
        Used at the job worker to clear originator for current thread.

      • threadedQueryInitiatorId

        public static String threadedQueryInitiatorId()
        Returns:
        originator set up by the job worker.