mirror of https://github.com/apache/nifi.git
NIFI-10503 Changed flow file references to FlowFile in GenerateTableFetch processor docs
Signed-off-by: Nathan Gough <thenatog@gmail.com> This closes #6577.
This commit is contained in:
Andrew Lim
Nathan Gough
parent
3ed87a2982
commit
2d5a8b8b0d
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@ -79,9 +79,9 @@ import java.util.stream.IntStream;
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+ "processor is intended to be run on the Primary Node only.\n\n"
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+ "This processor can accept incoming connections; the behavior of the processor is different whether incoming connections are provided:\n"
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+ " - If no incoming connection(s) are specified, the processor will generate SQL queries on the specified processor schedule. Expression Language is supported for many "
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+ "fields, but no flow file attributes are available. However the properties will be evaluated using the Variable Registry.\n"
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+ " - If incoming connection(s) are specified and no flow file is available to a processor task, no work will be performed.\n"
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+ " - If incoming connection(s) are specified and a flow file is available to a processor task, the flow file's attributes may be used in Expression Language for such fields "
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+ "fields, but no FlowFile attributes are available. However the properties will be evaluated using the Variable Registry.\n"
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+ " - If incoming connection(s) are specified and no FlowFile is available to a processor task, no work will be performed.\n"
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+ " - If incoming connection(s) are specified and a FlowFile is available to a processor task, the FlowFile's attributes may be used in Expression Language for such fields "
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+ "as Table Name and others. However, the Max-Value Columns and Columns to Return fields must be empty or refer to columns that are available in each specified table.")
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@Stateful(scopes = Scope.CLUSTER, description = "After performing a query on the specified table, the maximum values for "
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+ "the specified column(s) will be retained for use in future executions of the query. This allows the Processor "
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@ -89,8 +89,8 @@ import java.util.stream.IntStream;
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+ "incremental fetching, fetching of newly added rows, etc. To clear the maximum values, clear the state of the processor "
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+ "per the State Management documentation")
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@WritesAttributes({
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@WritesAttribute(attribute = "generatetablefetch.sql.error", description = "If the processor has incoming connections, and processing an incoming flow file causes "
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+ "a SQL Exception, the flow file is routed to failure and this attribute is set to the exception message."),
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@WritesAttribute(attribute = "generatetablefetch.sql.error", description = "If the processor has incoming connections, and processing an incoming FlowFile causes "
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+ "a SQL Exception, the FlowFile is routed to failure and this attribute is set to the exception message."),
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@WritesAttribute(attribute = "generatetablefetch.tableName", description = "The name of the database table to be queried."),
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@WritesAttribute(attribute = "generatetablefetch.columnNames", description = "The comma-separated list of column names used in the query."),
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@WritesAttribute(attribute = "generatetablefetch.whereClause", description = "Where clause used in the query to get the expected rows."),
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@ -112,7 +112,7 @@ import java.util.stream.IntStream;
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expressionLanguageScope = ExpressionLanguageScope.FLOWFILE_ATTRIBUTES, description = "Specifies an initial "
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+ "max value for max value columns. Properties should be added in the format `initial.maxvalue.<max_value_column>`. This value is only used the first time "
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+ "the table is accessed (when a Maximum Value Column is specified). In the case of incoming connections, the value is only used the first time for each table "
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+ "specified in the flow files.")
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+ "specified in the FlowFiles.")
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public class GenerateTableFetch extends AbstractDatabaseFetchProcessor {
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public static final PropertyDescriptor PARTITION_SIZE = new PropertyDescriptor.Builder()
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@ -145,8 +145,8 @@ public class GenerateTableFetch extends AbstractDatabaseFetchProcessor {
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.name("gen-table-output-flowfile-on-zero-results")
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.displayName("Output Empty FlowFile on Zero Results")
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.description("Depending on the specified properties, an execution of this processor may not result in any SQL statements generated. When this property "
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+ "is true, an empty flow file will be generated (having the parent of the incoming flow file if present) and transferred to the 'success' relationship. "
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+ "When this property is false, no output flow files will be generated.")
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+ "is true, an empty FlowFile will be generated (having the parent of the incoming FlowFile if present) and transferred to the 'success' relationship. "
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+ "When this property is false, no output FlowFiles will be generated.")
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.required(true)
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.allowableValues("true", "false")
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.defaultValue("false")
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@ -254,7 +254,7 @@ public class GenerateTableFetch extends AbstractDatabaseFetchProcessor {
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fileToProcess = session.get();
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if (fileToProcess == null) {
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// Incoming connection with no flow file available, do no work (see capability description)
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// Incoming connection with no FlowFile available, do no work (see capability description)
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return;
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}
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}
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@ -417,7 +417,7 @@ public class GenerateTableFetch extends AbstractDatabaseFetchProcessor {
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statePropertyMap.put(fullyQualifiedStateKey, newMaxValue);
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}
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} catch (ParseException | IOException | ClassCastException pice) {
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// Fail the whole thing here before we start creating flow files and such
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// Fail the whole thing here before we start creating FlowFiles and such
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throw new ProcessException(pice);
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}
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}
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@ -477,7 +477,7 @@ public class GenerateTableFetch extends AbstractDatabaseFetchProcessor {
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baseAttributes.put(FRAGMENT_ID, fragmentIdentifier);
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baseAttributes.put(FRAGMENT_COUNT, String.valueOf(numberOfFetches));
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// If there are no SQL statements to be generated, still output an empty flow file if specified by the user
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// If there are no SQL statements to be generated, still output an empty FlowFile if specified by the user
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if (numberOfFetches == 0 && outputEmptyFlowFileOnZeroResults) {
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FlowFile emptyFlowFile = (fileToProcess == null) ? session.create() : session.create(fileToProcess);
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Map<String, String> attributesToAdd = new HashMap<>();
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@ -23,7 +23,7 @@
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<body>
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<p>
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GenerateTableFetch uses its properties and the specified database connection to generate flow files
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GenerateTableFetch uses its properties and the specified database connection to generate FlowFiles
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containing SQL statements that can be used to fetch "pages" (aka "partitions") of data from a table.
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GenerateTableFetch executes a query to the database to determine the current row count and maximum value,
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and if Maximum Value Columns are specified, will collect the count of rows whose values for the Maximum
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@ -31,7 +31,7 @@
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fetching of "new" rows, rather than generating SQL to fetch the entire table each time. If no Maximum
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Value Columns are set, then the processor will generate SQL to fetch the entire table each time.
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</p>
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<p>
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In order to generate SQL that will fetch pages/partitions of data, by default GenerateTableFetch will
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generate SQL that orders the data based on the Maximum Value Columns (if present) and utilize the row
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@ -39,7 +39,7 @@
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and the partition size is 10, then the SQL for the first page might be "SELECT * FROM myTable LIMIT 10" and
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the second page might be "SELECT * FROM myTable OFFSET 10 LIMIT 10", and so on.
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</p>
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<p>
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Ordering the data can be an expensive operation depending on the database, the number of rows, etc.
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Alternatively, it is possible to specify a column whose values will be used to determine the pages, using
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@ -66,4 +66,4 @@
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sufficiently dense (not sparse) and fairly evenly distributed.
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</p>
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</body>
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</html>
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</html>
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