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<a href="/docs/2.9.0/quick-start/dotnet"
class=''
>.NET/C#</a>
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<li>
<a href="/docs/2.9.0/quick-start/cpp"
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>C++</a>
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<a href="/docs/2.9.0/quick-start/python"
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>Python</a>
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<a href="/docs/2.9.0/quick-start/nodejs"
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>Node.JS</a>
</li>
<li>
<a href="/docs/2.9.0/quick-start/sql"
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>SQL</a>
</li>
<li>
<a href="/docs/2.9.0/quick-start/php"
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>PHP</a>
</li>
<li>
<a href="/docs/2.9.0/quick-start/restapi"
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>REST API</a>
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<li>
<a href="/docs/2.9.0/installation/installing-using-docker"
class=''
>Installing Using Docker</a>
</li>
<li>
<a href="/docs/2.9.0/installation/deb-rpm"
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>Installing DEB or RPM package</a>
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<li><a href="/docs/2.9.0/installation/kubernetes/amazon-eks-deployment" class=''>Amazon EKS</a></li>
<li><a href="/docs/2.9.0/installation/kubernetes/azure-deployment" class=''>Azure Kubernetes Service</a></li>
<li><a href="/docs/2.9.0/installation/kubernetes/gke-deployment" class=''>Google Kubernetes Engine</a></li>
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</li>
<li>
<a href="/docs/2.9.0/installation/vmware-installation"
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<a href="/docs/2.9.0/understanding-configuration"
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>Understanding Configuration</a>
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<a href="/docs/2.9.0/setup"
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>Setting Up</a>
</li>
<li>
<a href="/docs/2.9.0/logging"
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>Configuring Logging</a>
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<li>
<a href="/docs/2.9.0/resources-injection"
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>Resources Injection</a>
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</li>
<li>
<a href="/docs/2.9.0/starting-nodes" class='' >Starting and Stopping Nodes</a>
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<li>
<button type='button' class='group-toggle collapsed '>Clustering<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<li>
<a href="/docs/2.9.0/clustering/clustering"
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>Overview</a>
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<a href="/docs/2.9.0/clustering/tcp-ip-discovery"
class=''
>TCP/IP Discovery</a>
</li>
<li>
<a href="/docs/2.9.0/clustering/zookeeper-discovery"
class=''
>ZooKeeper Discovery</a>
</li>
<li>
<a href="/docs/2.9.0/clustering/discovery-in-the-cloud"
class=''
>Discovery in the Cloud</a>
</li>
<li>
<a href="/docs/2.9.0/clustering/network-configuration"
class=''
>Network Configuration</a>
</li>
<li>
<a href="/docs/2.9.0/clustering/connect-client-nodes"
class=''
>Connecting Client Nodes</a>
</li>
<li>
<a href="/docs/2.9.0/clustering/baseline-topology"
class=''
>Baseline Topology</a>
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<li>
<a href="/docs/2.9.0/clustering/running-client-nodes-behind-nat"
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>Running Client Nodes Behind NAT</a>
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<button type='button' class='group-toggle collapsed '>Thin Clients<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<a href="/docs/2.9.0/thin-clients/getting-started-with-thin-clients"
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>Thin Clients Overview</a>
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<li>
<a href="/docs/2.9.0/thin-clients/java-thin-client"
class=''
>Java Thin Client</a>
</li>
<li>
<a href="/docs/2.9.0/thin-clients/dotnet-thin-client"
class=''
>.NET Thin Client</a>
</li>
<li>
<a href="/docs/2.9.0/thin-clients/cpp-thin-client"
class=''
>C++ Thin Client</a>
</li>
<li>
<a href="/docs/2.9.0/thin-clients/python-thin-client"
class=''
>Python Thin Client</a>
</li>
<li>
<a href="/docs/2.9.0/thin-clients/php-thin-client"
class=''
>PHP Thin Client</a>
</li>
<li>
<a href="/docs/2.9.0/thin-clients/nodejs-thin-client"
class=''
>Node.js Thin Client</a>
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<li>
<button
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<li><a href="/docs/2.9.0/binary-client-protocol/binary-client-protocol" class=''>Binary Client Protocol</a></li>
<li><a href="/docs/2.9.0/binary-client-protocol/data-format" class=''>Data Format</a></li>
<li><a href="/docs/2.9.0/binary-client-protocol/key-value-queries" class=''>Key-Value Queries</a></li>
<li><a href="/docs/2.9.0/binary-client-protocol/sql-and-scan-queries" class=''>SQL and Scan Queries</a></li>
<li><a href="/docs/2.9.0/binary-client-protocol/binary-type-metadata" class=''>Binary Types Metadata</a></li>
<li><a href="/docs/2.9.0/binary-client-protocol/cache-configuration" class=''>Cache Configuration</a></li>
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</li>
</nav>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Data Modeling<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<li>
<a href="/docs/2.9.0/data-modeling/data-modeling"
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>Introduction</a>
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<li>
<a href="/docs/2.9.0/data-modeling/data-partitioning"
class=''
>Data Partitioning</a>
</li>
<li>
<a href="/docs/2.9.0/data-modeling/affinity-collocation"
class=''
>Affinity Colocation</a>
</li>
<li>
<a href="/docs/2.9.0/data-modeling/binary-marshaller"
class=''
>Binary Marshaller</a>
</li>
</nav>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Configuring Memory<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class='nav-group collapsed'>
<li>
<a href="/docs/2.9.0/memory-architecture"
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>Memory Architecture</a>
</li>
<li>
<a href="/docs/2.9.0/memory-configuration/data-regions"
class=''
>Configuring Data Regions</a>
</li>
<li>
<a href="/docs/2.9.0/memory-configuration/eviction-policies"
class=''
>Eviction Policies</a>
</li>
<li>
<a href="/docs/2.9.0/memory-configuration/replacement-policies"
class=''
>Replacement Policies</a>
</li>
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</li>
<li>
<button type='button' class='group-toggle collapsed '>Configuring Persistence<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class='nav-group collapsed'>
<li>
<a href="/docs/2.9.0/persistence/native-persistence"
class=''
>Ignite Persistence</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/external-storage"
class=''
>External Storage</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/swap"
class=''
>Swapping</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/custom-cache-store"
class=''
>Implementing Custom Cache Store</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/snapshot-directory"
class=''
>Configuring Snapshot Directory</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/disk-compression"
class=''
>Disk Compression</a>
</li>
<li>
<a href="/docs/2.9.0/persistence/persistence-tuning"
class=''
>Tuning Persistence</a>
</li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/snapshots/snapshots" class='' >Cluster Snapshots</a>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Configuring Caches<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class='nav-group collapsed'>
<li>
<a href="/docs/2.9.0/configuring-caches/configuration-overview"
class=''
>Cache Configuration</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/configuring-backups"
class=''
>Configuring Partition Backups</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/partition-loss-policy"
class=''
>Partition Loss Policy</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/atomicity-modes"
class=''
>Atomicity Modes</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/expiry-policies"
class=''
>Expiry Policy</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/on-heap-caching"
class=''
>On-Heap Caching</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/cache-groups"
class=''
>Cache Groups</a>
</li>
<li>
<a href="/docs/2.9.0/configuring-caches/near-cache"
class=''
>Near Caches</a>
</li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/data-rebalancing" class='' >Data Rebalancing</a>
</li>
<li>
<a href="/docs/2.9.0/data-streaming" class='' >Data Streaming</a>
</li>
<li>
<button type='button' class='group-toggle expanded '>Using Key-Value API<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class='nav-group expanded'>
<li>
<a href="/docs/2.9.0/key-value-api/basic-cache-operations"
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>Basic Cache Operations</a>
</li>
<li>
<a href="/docs/2.9.0/key-value-api/binary-objects"
class=''
>Working with Binary Objects</a>
</li>
<li>
<a href="/docs/2.9.0/key-value-api/using-cache-queries"
class='active'
>Using Cache Queries</a>
</li>
<li>
<a href="/docs/2.9.0/read-repair"
class=''
>Read Repair</a>
</li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/key-value-api/transactions" class='' >Performing Transactions</a>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Working with SQL<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class='nav-group collapsed'>
<li>
<a href="/docs/2.9.0/SQL/sql-introduction"
class=''
>Introduction</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/schemas"
class=''
>Understanding Schemas</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/indexes"
class=''
>Defining Indexes</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/sql-api"
class=''
>Using SQL API</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/distributed-joins"
class=''
>Distributed Joins</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/custom-sql-func"
class=''
>Custom SQL Functions</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/JDBC/jdbc-driver"
class=''
>JDBC Driver</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/JDBC/jdbc-client-driver"
class=''
>JDBC Client Driver</a>
</li>
<li>
<button
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<li><a href="/docs/2.9.0/SQL/ODBC/odbc-driver" class=''>ODBC Driver</a></li>
<li><a href="/docs/2.9.0//SQL/ODBC/connection-string-dsn" class=''>Connection String and DSN</a></li>
<li><a href="/docs/2.9.0/SQL/ODBC/querying-modifying-data" class=''>Querying and Modifying Data</a></li>
<li><a href="/docs/2.9.0/SQL/ODBC/specification" class=''>Specification</a></li>
<li><a href="/docs/2.9.0/SQL/ODBC/data-types" class=''>Data Types</a></li>
<li><a href="/docs/2.9.0/SQL/ODBC/error-codes" class=''>Error Codes</a></li>
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</li>
<li>
<a href="/docs/2.9.0/transactions/mvcc"
class=''
>Multiversion Concurrency Control</a>
</li>
<li>
<a href="/docs/2.9.0/SQL/sql-statistics"
class=''
>SQL Statistics</a>
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<li>
<button type='button' class='group-toggle collapsed '>SQL Reference<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<a href="/docs/2.9.0/sql-reference/sql-conformance"
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>SQL Conformance</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/ddl"
class=''
>Data Definition Language (DDL)</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/dml"
class=''
>Data Manipulation Language (DML)</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/transactions"
class=''
>Transactions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/operational-commands"
class=''
>Operational Commands</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/aggregate-functions"
class=''
>Aggregate functions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/numeric-functions"
class=''
>Numeric Functions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/string-functions"
class=''
>String Functions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/date-time-functions"
class=''
>Data and Time Functions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/system-functions"
class=''
>System Functions</a>
</li>
<li>
<a href="/docs/2.9.0/sql-reference/data-types"
class=''
>Data Types</a>
</li>
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</li>
<li>
<button type='button' class='group-toggle collapsed '>Distributed Computing<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<li>
<a href="/docs/2.9.0/distributed-computing/distributed-computing"
class=''
>Distributed Computing API</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/cluster-groups"
class=''
>Cluster Groups</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/executor-service"
class=''
>Executor Service</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/map-reduce"
class=''
>MapReduce API</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/load-balancing"
class=''
>Load Balancing</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/fault-tolerance"
class=''
>Fault Tolerance</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/job-scheduling"
class=''
>Job Scheduling</a>
</li>
<li>
<a href="/docs/2.9.0/distributed-computing/collocated-computations"
class=''
>Colocating Computations with Data</a>
</li>
</nav>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Code Deployment<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<li>
<a href="/docs/2.9.0/code-deployment/deploying-user-code"
class=''
>Deploying User Code</a>
</li>
<li>
<a href="/docs/2.9.0/code-deployment/peer-class-loading"
class=''
>Peer Class Loading</a>
</li>
</nav>
</li>
<li>
<button type='button' class='group-toggle collapsed '>Machine Learning<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
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<li>
<a href="/docs/2.9.0/machine-learning/machine-learning"
class=''
>Machine Learning</a>
</li>
<li>
<a href="/docs/2.9.0/machine-learning/partition-based-dataset"
class=''
>Partition Based Dataset</a>
</li>
<li>
<a href="/docs/2.9.0/machine-learning/updating-trained-models"
class=''
>Updating Trained Models</a>
</li>
<li>
<button
type='button'
class='collapsed '>Binary Classification<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
<li><a href="/docs/2.9.0/machine-learning/binary-classification/introduction" class=''>Introduction</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/linear-svm" class=''>Linear SVM (Support Vector Machine)</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/decision-trees" class=''>Decision Trees</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/multilayer-perceptron" class=''>Multilayer Perceptron</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/logistic-regression" class=''>Logistic Regression</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/knn-classification" class=''>k-NN Classification</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/ann" class=''>ANN (Approximate Nearest Neighbor)</a></li>
<li><a href="/docs/2.9.0/machine-learning/binary-classification/naive-bayes" class=''>Naive Bayes</a></li>
</nav>
</li>
<li>
<button
type='button'
class='collapsed '>Regression<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
<li><a href="/docs/2.9.0/machine-learning/regression/introduction" class=''>Introduction</a></li>
<li><a href="/docs/2.9.0/machine-learning/regression/linear-regression" class=''>Linear Regression</a></li>
<li><a href="/docs/2.9.0/machine-learning/regression/decision-trees-regression" class=''>Decision Trees Regression</a></li>
<li><a href="/docs/2.9.0/machine-learning/regression/knn-regression" class=''>k-NN Regression</a></li>
</nav>
</li>
<li>
<button
type='button'
class='collapsed '>Clustering<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
<li><a href="/docs/2.9.0/machine-learning/clustering/introduction" class=''>Introduction</a></li>
<li><a href="/docs/2.9.0/machine-learning/clustering/k-means-clustering" class=''>K-Means Clustering</a></li>
<li><a href="/docs/2.9.0/machine-learning/clustering/gaussian-mixture" class=''>Gaussian mixture (GMM)</a></li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/machine-learning/preprocessing"
class=''
>Preprocessing</a>
</li>
<li>
<button
type='button'
class='collapsed '>Model Selection<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
<li><a href="/docs/2.9.0/machine-learning/model-selection/introduction" class=''>Introduction</a></li>
<li><a href="/docs/2.9.0/machine-learning/model-selection/evaluator" class=''>Evaluator</a></li>
<li><a href="/docs/2.9.0/machine-learning/model-selection/split-the-dataset-on-test-and-train-datasets" class=''>Split the dataset on test and train datasets</a></li>
<li><a href="/docs/2.9.0/machine-learning/model-selection/hyper-parameter-tuning" class=''>Hyper-parameter tuning</a></li>
<li><a href="/docs/2.9.0/machine-learning/model-selection/pipeline-api" class=''>Pipeline API</a></li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/machine-learning/multiclass-classification"
class=''
>Multiclass Classification</a>
</li>
<li>
<button
type='button'
class='collapsed '>Ensemble Methods<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
<li><a href="/docs/2.9.0/machine-learning/ensemble-methods/introduction" class=''></a></li>
<li><a href="/docs/2.9.0/machine-learning/ensemble-methods/stacking" class=''>Stacking</a></li>
<li><a href="/docs/2.9.0/machine-learning/ensemble-methods/baggin" class=''>Bagging</a></li>
<li><a href="/docs/2.9.0/machine-learning/ensemble-methods/random-forest" class=''>Random Forest</a></li>
<li><a href="/docs/2.9.0/machine-learning/ensemble-methods/gradient-boosting" class=''>Gradient Boosting</a></li>
</nav>
</li>
<li>
<a href="/docs/2.9.0/machine-learning/recommendation-systems"
class=''
>Recommendation Systems</a>
</li>
<li>
<button
type='button'
class='collapsed '>Importing Model<img class="state-indicator" src="/assets/images/left-nav-arrow.svg" width="6" height="10"></button>
<nav class="sub_pages collapsed">
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<article data-swiftype-index='true'>
<a class='edit-link' href="https://github.com/apache/ignite/tree/IGNITE-7595/docs/_docs/key-value-api/using-cache-queries.adoc" target="_blank">Edit</a>
<h1>Using Cache Queries</h1>
<div class="sect1">
<h2 id="overview">Overview</h2>
<div class="sectionbody">
<div class="paragraph">
<p><code>IgniteCache</code> has several query methods, all of which receive a subclass of the <code>Query</code> class and return a <code>QueryCursor</code>.
Available types of queries: <code>ScanQuery</code>, <code>IndexQuery</code>, <code>TextQuery</code>.</p>
</div>
<div class="paragraph">
<p>A <code>Query</code> represents an abstract paginated query to be executed on a cache.
The page size is configurable via the <code>Query.setPageSize(&#8230;&#8203;)</code> method (default is 1024).</p>
</div>
<div class="paragraph">
<p><code>QueryCursor</code> represents the query result set and allows for transparent page-by-page iteration.
When a user starts iterating over the last page, <code>QueryCursos</code> automatically requests the next page in the background.
For cases when pagination is not needed, you can use the <code>QueryCursor.getAll()</code> method, which fetches the entries and stores them in a collection.</p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<div class="title">Note</div>
</td>
<td class="content">
<h3 id="closing-cursors" class="discrete">Closing Cursors</h3>
<div class="paragraph">
<p>Cursors close automatically when you call the <code>QueryCursor.getAll()</code> method. If you are iterating over the cursor in a for loop or explicitly getting an <code>Iterator</code>, you must close the cursor explicitly or use a try-with-resources statement.</p>
</div>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="executing-scan-queries">Executing Scan Queries</h2>
<div class="sectionbody">
<div class="paragraph">
<p>A scan query is a simple search query used to retrieve data from a cache in a distributed manner. When executed without parameters, a scan query returns all entries from the cache.</p>
</div>
<code-tabs><code-tab data-tab='Java'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="nc">IgniteCache</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">cache</span> <span class="o">=</span> <span class="n">ignite</span><span class="o">.</span><span class="na">getOrCreateCache</span><span class="o">(</span><span class="s">"myCache"</span><span class="o">);</span>
<span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span><span class="k">new</span> <span class="nc">ScanQuery</span><span class="o">&lt;&gt;());</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C#/.NET'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="csharp"><span class="kt">var</span> <span class="n">cursor</span> <span class="p">=</span> <span class="n">cache</span><span class="p">.</span><span class="nf">Query</span><span class="p">(</span><span class="k">new</span> <span class="n">ScanQuery</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;());</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C++'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="cpp"><span class="n">Cache</span><span class="o">&lt;</span><span class="kt">int64_t</span><span class="p">,</span> <span class="n">Person</span><span class="o">&gt;</span> <span class="n">cache</span> <span class="o">=</span> <span class="n">ignite</span><span class="p">.</span><span class="n">GetOrCreateCache</span><span class="o">&lt;</span><span class="kt">int64_t</span><span class="p">,</span> <span class="n">ignite</span><span class="o">::</span><span class="n">Person</span><span class="o">&gt;</span><span class="p">(</span><span class="s">"personCache"</span><span class="p">);</span>
<span class="n">QueryCursor</span><span class="o">&lt;</span><span class="kt">int64_t</span><span class="p">,</span> <span class="n">Person</span><span class="o">&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="p">.</span><span class="n">Query</span><span class="p">(</span><span class="n">ScanQuery</span><span class="p">());</span></code></pre>
</div>
</div></code-tab></code-tabs>
<div class="paragraph">
<p>Scan queries return entries that match a predicate, if specified. The predicate is applied on the remote nodes.</p>
</div>
<code-tabs><code-tab data-tab='Java'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="nc">IgniteCache</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">cache</span> <span class="o">=</span> <span class="n">ignite</span><span class="o">.</span><span class="na">getOrCreateCache</span><span class="o">(</span><span class="s">"myCache"</span><span class="o">);</span>
<span class="c1">// Find the persons who earn more than 1,000.</span>
<span class="nc">IgniteBiPredicate</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">filter</span> <span class="o">=</span> <span class="o">(</span><span class="n">key</span><span class="o">,</span> <span class="n">p</span><span class="o">)</span> <span class="o">-&gt;</span> <span class="n">p</span><span class="o">.</span><span class="na">getSalary</span><span class="o">()</span> <span class="o">&gt;</span> <span class="mi">1000</span><span class="o">;</span>
<span class="k">try</span> <span class="o">(</span><span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">qryCursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span><span class="k">new</span> <span class="nc">ScanQuery</span><span class="o">&lt;&gt;(</span><span class="n">filter</span><span class="o">)))</span> <span class="o">{</span>
<span class="n">qryCursor</span><span class="o">.</span><span class="na">forEach</span><span class="o">(</span>
<span class="n">entry</span> <span class="o">-&gt;</span> <span class="nc">System</span><span class="o">.</span><span class="na">out</span><span class="o">.</span><span class="na">println</span><span class="o">(</span><span class="s">"Key = "</span> <span class="o">+</span> <span class="n">entry</span><span class="o">.</span><span class="na">getKey</span><span class="o">()</span> <span class="o">+</span> <span class="s">", Value = "</span> <span class="o">+</span> <span class="n">entry</span><span class="o">.</span><span class="na">getValue</span><span class="o">()));</span>
<span class="o">}</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C#/.NET'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="csharp"><span class="k">class</span> <span class="nc">SalaryFilter</span> <span class="p">:</span> <span class="n">ICacheEntryFilter</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;</span>
<span class="p">{</span>
<span class="k">public</span> <span class="kt">bool</span> <span class="nf">Invoke</span><span class="p">(</span><span class="n">ICacheEntry</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;</span> <span class="n">entry</span><span class="p">)</span>
<span class="p">{</span>
<span class="k">return</span> <span class="n">entry</span><span class="p">.</span><span class="n">Value</span><span class="p">.</span><span class="n">Salary</span> <span class="p">&gt;</span> <span class="m">1000</span><span class="p">;</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="k">public</span> <span class="k">static</span> <span class="k">void</span> <span class="nf">ScanQueryFilterDemo</span><span class="p">()</span>
<span class="p">{</span>
<span class="kt">var</span> <span class="n">ignite</span> <span class="p">=</span> <span class="n">Ignition</span><span class="p">.</span><span class="nf">Start</span><span class="p">();</span>
<span class="kt">var</span> <span class="n">cache</span> <span class="p">=</span> <span class="n">ignite</span><span class="p">.</span><span class="n">GetOrCreateCache</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;(</span><span class="s">"person_cache"</span><span class="p">);</span>
<span class="n">cache</span><span class="p">.</span><span class="nf">Put</span><span class="p">(</span><span class="m">1</span><span class="p">,</span> <span class="k">new</span> <span class="n">Person</span> <span class="p">{</span><span class="n">Name</span> <span class="p">=</span> <span class="s">"person1"</span><span class="p">,</span> <span class="n">Salary</span> <span class="p">=</span> <span class="m">1001</span><span class="p">});</span>
<span class="n">cache</span><span class="p">.</span><span class="nf">Put</span><span class="p">(</span><span class="m">2</span><span class="p">,</span> <span class="k">new</span> <span class="n">Person</span> <span class="p">{</span><span class="n">Name</span> <span class="p">=</span> <span class="s">"person2"</span><span class="p">,</span> <span class="n">Salary</span> <span class="p">=</span> <span class="m">999</span><span class="p">});</span>
<span class="k">using</span> <span class="p">(</span><span class="kt">var</span> <span class="n">cursor</span> <span class="p">=</span> <span class="n">cache</span><span class="p">.</span><span class="nf">Query</span><span class="p">(</span><span class="k">new</span> <span class="n">ScanQuery</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;(</span><span class="k">new</span> <span class="nf">SalaryFilter</span><span class="p">())))</span>
<span class="p">{</span>
<span class="k">foreach</span> <span class="p">(</span><span class="kt">var</span> <span class="n">entry</span> <span class="k">in</span> <span class="n">cursor</span><span class="p">)</span>
<span class="p">{</span>
<span class="n">Console</span><span class="p">.</span><span class="nf">WriteLine</span><span class="p">(</span><span class="s">"Key = "</span> <span class="p">+</span> <span class="n">entry</span><span class="p">.</span><span class="n">Key</span> <span class="p">+</span> <span class="s">", Value = "</span> <span class="p">+</span> <span class="n">entry</span><span class="p">.</span><span class="n">Value</span><span class="p">);</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="p">}</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C++' data-unavailable='true'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code>This API is not presently available for C++.</code></pre>
</div>
</div></code-tab></code-tabs>
<div class="paragraph">
<p>Scan queries also support an optional transformer closure which lets you convert the entry on the server node before sending it back. This is useful, for example, when you want to fetch only several fields of a large object and want to minimize the network traffic. The example below shows how to fetch only the keys without sending the values.</p>
</div>
<code-tabs><code-tab data-tab='Java'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="nc">IgniteCache</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">cache</span> <span class="o">=</span> <span class="n">ignite</span><span class="o">.</span><span class="na">getOrCreateCache</span><span class="o">(</span><span class="s">"myCache"</span><span class="o">);</span>
<span class="c1">// Get only keys for persons earning more than 1,000.</span>
<span class="nc">List</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">&gt;</span> <span class="n">keys</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span><span class="k">new</span> <span class="nc">ScanQuery</span><span class="o">&lt;&gt;(</span>
<span class="c1">// Remote filter</span>
<span class="o">(</span><span class="nc">IgniteBiPredicate</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;)</span> <span class="o">(</span><span class="n">k</span><span class="o">,</span> <span class="n">p</span><span class="o">)</span> <span class="o">-&gt;</span> <span class="n">p</span><span class="o">.</span><span class="na">getSalary</span><span class="o">()</span> <span class="o">&gt;</span> <span class="mi">1000</span><span class="o">),</span>
<span class="c1">// Transformer</span>
<span class="o">(</span><span class="nc">IgniteClosure</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;,</span> <span class="nc">Integer</span><span class="o">&gt;)</span> <span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">::</span><span class="n">getKey</span><span class="o">).</span><span class="na">getAll</span><span class="o">();</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C#/.NET' data-unavailable='true'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code>This API is not presently available for C#/.NET.</code></pre>
</div>
</div></code-tab><code-tab data-tab='C++' data-unavailable='true'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code>This API is not presently available for C++.</code></pre>
</div>
</div></code-tab></code-tabs>
</div>
</div>
<div class="sect1">
<h2 id="local-scan-query">Local Scan Query</h2>
<div class="sectionbody">
<div class="paragraph">
<p>By default, a scan query is distributed to all nodes.
However, you can execute the query locally, in which case the query runs against the data stored on the local node (i.e. the node where the query is executed).</p>
</div>
<code-tabs><code-tab data-tab='Java'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span>
<span class="o">.</span><span class="na">query</span><span class="o">(</span><span class="k">new</span> <span class="nc">ScanQuery</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;().</span><span class="na">setLocal</span><span class="o">(</span><span class="kc">true</span><span class="o">));</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C#/.NET'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="csharp"><span class="kt">var</span> <span class="n">query</span> <span class="p">=</span> <span class="k">new</span> <span class="n">ScanQuery</span><span class="p">&lt;</span><span class="kt">int</span><span class="p">,</span> <span class="n">Person</span><span class="p">&gt;</span> <span class="p">{</span><span class="n">Local</span> <span class="p">=</span> <span class="k">true</span><span class="p">};</span>
<span class="kt">var</span> <span class="n">cursor</span> <span class="p">=</span> <span class="n">cache</span><span class="p">.</span><span class="nf">Query</span><span class="p">(</span><span class="n">query</span><span class="p">);</span></code></pre>
</div>
</div></code-tab><code-tab data-tab='C++'><div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="cpp"><span class="n">ScanQuery</span> <span class="n">sq</span><span class="p">;</span>
<span class="n">sq</span><span class="p">.</span><span class="n">SetLocal</span><span class="p">(</span><span class="nb">true</span><span class="p">);</span>
<span class="n">QueryCursor</span><span class="o">&lt;</span><span class="kt">int64_t</span><span class="p">,</span> <span class="n">Person</span><span class="o">&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="p">.</span><span class="n">Query</span><span class="p">(</span><span class="n">sq</span><span class="p">);</span></code></pre>
</div>
</div></code-tab></code-tabs>
</div>
</div>
<div class="sect1">
<h2 id="executing-index-queries">Executing Index Queries</h2>
<div class="sectionbody">
<div class="admonitionblock warning">
<table>
<tr>
<td class="icon">
<div class="title">Warning</div>
</td>
<td class="content">
<div class="paragraph">
<p>Experimental API. Introduced since Apache Ignite 2.12. Only Java API is supported. Please send your questions and bug reports
to <a href="mailto:user@ignite.apache.org">user@ignite.apache.org</a>.</p>
</div>
</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>Index queries work over distributed indexes and retrieve cache entries that match the specified query. <code>QueryCursor</code>
delivers sorted cache entries by the order defined for queried index. <code>IndexQuery</code> can be used if a low amount of data
matches filtering criteria. For such cases, <code>ScanQuery</code> usage is not optimal: it firstly extracts all cache entries and
then applies a filter to them. <code>IndexQuery</code> relies on index tree structure and filters most of the entries without extracting.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="c1">// Create index by 2 fields (orgId, salary).</span>
<span class="nc">QueryEntity</span> <span class="n">personEntity</span> <span class="o">=</span> <span class="k">new</span> <span class="nc">QueryEntity</span><span class="o">(</span><span class="nc">Integer</span><span class="o">.</span><span class="na">class</span><span class="o">,</span> <span class="nc">Person</span><span class="o">.</span><span class="na">class</span><span class="o">)</span>
<span class="o">.</span><span class="na">setFields</span><span class="o">(</span><span class="k">new</span> <span class="nc">LinkedHashMap</span><span class="o">&lt;</span><span class="nc">String</span><span class="o">,</span> <span class="nc">String</span><span class="o">&gt;()</span> <span class="o">{{</span>
<span class="n">put</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="nc">Integer</span><span class="o">.</span><span class="na">class</span><span class="o">.</span><span class="na">getName</span><span class="o">());</span>
<span class="n">put</span><span class="o">(</span><span class="s">"salary"</span><span class="o">,</span> <span class="nc">Integer</span><span class="o">.</span><span class="na">class</span><span class="o">.</span><span class="na">getName</span><span class="o">());</span>
<span class="o">}})</span>
<span class="o">.</span><span class="na">setIndexes</span><span class="o">(</span><span class="nc">Collections</span><span class="o">.</span><span class="na">singletonList</span><span class="o">(</span>
<span class="k">new</span> <span class="nf">QueryIndex</span><span class="o">(</span><span class="nc">Arrays</span><span class="o">.</span><span class="na">asList</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="s">"salary"</span><span class="o">),</span> <span class="nc">QueryIndexType</span><span class="o">.</span><span class="na">SORTED</span><span class="o">)</span>
<span class="o">.</span><span class="na">setName</span><span class="o">(</span><span class="s">"ORG_SALARY_IDX"</span><span class="o">)</span>
<span class="o">));</span>
<span class="nc">CacheConfiguration</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">ccfg</span> <span class="o">=</span> <span class="k">new</span> <span class="nc">CacheConfiguration</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;(</span><span class="s">"entityCache"</span><span class="o">)</span>
<span class="o">.</span><span class="na">setQueryEntities</span><span class="o">(</span><span class="nc">Collections</span><span class="o">.</span><span class="na">singletonList</span><span class="o">(</span><span class="n">personEntity</span><span class="o">));</span>
<span class="nc">IgniteCache</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;</span> <span class="n">cache</span> <span class="o">=</span> <span class="n">ignite</span><span class="o">.</span><span class="na">getOrCreateCache</span><span class="o">(</span><span class="n">ccfg</span><span class="o">);</span>
<span class="c1">// Find the persons who work in Organization 1.</span>
<span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span>
<span class="k">new</span> <span class="nc">IndexQuery</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;(</span><span class="nc">Person</span><span class="o">.</span><span class="na">class</span><span class="o">,</span> <span class="s">"ORG_SALARY_IDX"</span><span class="o">)</span>
<span class="o">.</span><span class="na">setCriteria</span><span class="o">(</span><span class="n">eq</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="mi">1</span><span class="o">))</span>
<span class="o">);</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>Index query criteria are defined in <code>IndexQueryCriteriaBuilder</code>. The goal of the criteria is to build a valid range to
traverse the index tree. For this reason, criteria fields have to match the specified index. For example, if there is an
index defined with (A, B) set, then valid criteria sets are (A) and (A, B). Criteria with the single (B) field are invalid
because the field (B) is not a prefix set of the specified index fields, and it&#8217;s impossible to build a narrow index range
with it.</p>
</div>
<div class="admonitionblock note">
<table>
<tr>
<td class="icon">
<div class="title">Note</div>
</td>
<td class="content">
<div class="paragraph">
<p>Criteria are joined by the AND operator. It is also possible to use multiple criteria for the same field.</p>
</div>
</td>
</tr>
</table>
</div>
<div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="c1">// Find the persons who work in Organization 1 and have salary more than 1,000.</span>
<span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span>
<span class="k">new</span> <span class="nc">IndexQuery</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;(</span><span class="nc">Person</span><span class="o">.</span><span class="na">class</span><span class="o">,</span> <span class="s">"ORG_SALARY_IDX"</span><span class="o">)</span>
<span class="o">.</span><span class="na">setCriteria</span><span class="o">(</span><span class="n">eq</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="mi">1</span><span class="o">),</span> <span class="n">gt</span><span class="o">(</span><span class="s">"salary"</span><span class="o">,</span> <span class="mi">1000</span><span class="o">))</span>
<span class="o">);</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>The index name is an optional parameter. In this case, Ignite tries to figure out the index by itself using specified criteria fields.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="c1">// Ignite finds suitable index "ORG_SALARY_IDX" by specified criterion field "orgId".</span>
<span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span>
<span class="k">new</span> <span class="nc">IndexQuery</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;(</span><span class="nc">Person</span><span class="o">.</span><span class="na">class</span><span class="o">)</span>
<span class="o">.</span><span class="na">setCriteria</span><span class="o">(</span><span class="n">eq</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="mi">1</span><span class="o">))</span>
<span class="o">);</span></code></pre>
</div>
</div>
<div class="paragraph">
<p>For the empty criteria list, a full scan of the specified index is performed. If index name is also not specified, then the
PrimaryKey index is used.</p>
</div>
<div class="sect2">
<h3 id="additional-filtering">Additional filtering</h3>
<div class="paragraph">
<p><code>IndexQuery</code> also supports an optional predicate, the same as <code>ScanQuery</code> has. It&#8217;s suitable for additional cache entry
filtering in cases when a filter doesn&#8217;t match an index tree range. For example, it contains some logic, the "OR"
operations, or fields that are not the part of the index.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="rouge highlight"><code data-lang="java"><span class="c1">// Find the persons who work in Organization 1 and whose name contains 'Vasya'.</span>
<span class="nc">QueryCursor</span><span class="o">&lt;</span><span class="nc">Cache</span><span class="o">.</span><span class="na">Entry</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;&gt;</span> <span class="n">cursor</span> <span class="o">=</span> <span class="n">cache</span><span class="o">.</span><span class="na">query</span><span class="o">(</span>
<span class="k">new</span> <span class="nc">IndexQuery</span><span class="o">&lt;</span><span class="nc">Integer</span><span class="o">,</span> <span class="nc">Person</span><span class="o">&gt;(</span><span class="nc">Person</span><span class="o">.</span><span class="na">class</span><span class="o">)</span>
<span class="o">.</span><span class="na">setCriteria</span><span class="o">(</span><span class="n">eq</span><span class="o">(</span><span class="s">"orgId"</span><span class="o">,</span> <span class="mi">1</span><span class="o">))</span>
<span class="o">.</span><span class="na">setFilter</span><span class="o">((</span><span class="n">k</span><span class="o">,</span> <span class="n">v</span><span class="o">)</span> <span class="o">-&gt;</span> <span class="n">v</span><span class="o">.</span><span class="na">getName</span><span class="o">().</span><span class="na">contains</span><span class="o">(</span><span class="s">"Vasya"</span><span class="o">))</span>
<span class="o">);</span></code></pre>
</div>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="related-topics">Related Topics</h2>
<div class="sectionbody">
<div class="ulist">
<ul>
<li>
<p><a href="/docs/2.9.0/restapi#sql-scan-query-execute">Execute scan query via REST API</a></p>
</li>
<li>
<p><a href="/docs/2.9.0/events/events#cache-query-events">Cache Query Events</a></p>
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<p><a href="/docs/2.9.0/SQL/indexes">Defining Indexes</a></p>
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<li><a href="#local-scan-query">Local Scan Query</a></li>
<li><a href="#executing-index-queries">Executing Index Queries</a>
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