public class QueryRewriter extends Object
Modifier and Type | Class and Description |
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static class |
QueryRewriter.CostEstimator
The different methods for estimating the join cost.
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Modifier and Type | Field and Description |
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static double |
ALLOWED_STEP_INCREASE_DEFAULT |
static String |
ALLOWED_STEP_INCREASE_KEY
How much we allow the query cost (number of rows) to increase at each step.
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static double |
ALLOWED_TOTAL_INCREASE_DEFAULT |
static String |
ALLOWED_TOTAL_INCREASE_KEY
How much we allow the query cost (number of rows) to for new plans.
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static String |
CONFIG_PREFIX |
static String |
COST_ESTIMATOR_DEFAULT |
static String |
COST_ESTIMATOR_KEY
Whether we should use histograms or column selectivity to estimate the join size.
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Constructor and Description |
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QueryRewriter() |
Modifier and Type | Method and Description |
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Formula |
rewrite(Formula baseFormula,
RDBMSDataStore dataStore)
Rewrite the query to minimize the execution time while trading off query size.
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public static final String CONFIG_PREFIX
public static final String ALLOWED_TOTAL_INCREASE_KEY
public static final double ALLOWED_TOTAL_INCREASE_DEFAULT
public static final String ALLOWED_STEP_INCREASE_KEY
public static final double ALLOWED_STEP_INCREASE_DEFAULT
public static final String COST_ESTIMATOR_KEY
public static final String COST_ESTIMATOR_DEFAULT
public Formula rewrite(Formula baseFormula, RDBMSDataStore dataStore)
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