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[Imporve] [CDC Base] Add a fast sampling method that supports character types #5179

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merged 2 commits into from
Aug 10, 2023
Merged

[Imporve] [CDC Base] Add a fast sampling method that supports character types #5179

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4c70f76
[Imporve] [CDC Base] Add a fast sampling method that supports charact…
ic4y Jul 29, 2023
60aed0e
Merge branch 'dev' into dev-addsampskip
ic4y Aug 2, 2023
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23 changes: 22 additions & 1 deletion ...unnel/connectors/cdc/base/source/enumerator/splitter/AbstractJdbcSourceChunkSplitter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -112,6 +112,19 @@ private List<ChunkRange> splitTableIntoChunks(
final int chunkSize = sourceConfig.getSplitSize();
final double distributionFactorUpper = sourceConfig.getDistributionFactorUpper();
final double distributionFactorLower = sourceConfig.getDistributionFactorLower();
final int sampleShardingThreshold = sourceConfig.getSampleShardingThreshold();

log.info(
"Splitting table {} into chunks, split column: {}, min: {}, max: {}, chunk size: {}, "
+ "distribution factor upper: {}, distribution factor lower: {}, sample sharding threshold: {}",
tableId,
splitColumnName,
min,
max,
chunkSize,
distributionFactorUpper,
distributionFactorLower,
sampleShardingThreshold);

if (isEvenlySplitColumn(splitColumn)) {
long approximateRowCnt = queryApproximateRowCnt(jdbc, tableId);
Expand All @@ -130,7 +143,7 @@ private List<ChunkRange> splitTableIntoChunks(
} else {
int shardCount = (int) (approximateRowCnt / chunkSize);
int inverseSamplingRate = sourceConfig.getInverseSamplingRate();
if (sourceConfig.getSampleShardingThreshold() < shardCount) {
if (sampleShardingThreshold < shardCount) {
// It is necessary to ensure that the number of data rows sampled by the
// sampling rate is greater than the number of shards.
// Otherwise, if the sampling rate is too low, it may result in an insufficient
Expand All @@ -144,9 +157,17 @@ private List<ChunkRange> splitTableIntoChunks(
chunkSize);
inverseSamplingRate = chunkSize;
}
log.info(
"Use sampling sharding for table {}, the sampling rate is {}",
tableId,
inverseSamplingRate);
Object[] sample =
sampleDataFromColumn(
jdbc, tableId, splitColumnName, inverseSamplingRate);
log.info(
"Sample data from table {} end, the sample size is {}",
tableId,
sample.length);
return efficientShardingThroughSampling(
tableId, sample, approximateRowCnt, shardCount);
}
Expand Down
3 changes: 2 additions & 1 deletion ...apache/seatunnel/connectors/seatunnel/cdc/mysql/source/MySqlIncrementalSourceFactory.java
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Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,8 @@ public OptionRule optionRule() {
JdbcSourceOptions.CONNECTION_POOL_SIZE,
JdbcSourceOptions.CHUNK_KEY_EVEN_DISTRIBUTION_FACTOR_LOWER_BOUND,
JdbcSourceOptions.CHUNK_KEY_EVEN_DISTRIBUTION_FACTOR_UPPER_BOUND,
JdbcSourceOptions.SAMPLE_SHARDING_THRESHOLD)
JdbcSourceOptions.SAMPLE_SHARDING_THRESHOLD,
JdbcSourceOptions.INVERSE_SAMPLING_RATE)
.optional(MySqlSourceOptions.STARTUP_MODE, MySqlSourceOptions.STOP_MODE)
.conditional(
MySqlSourceOptions.STARTUP_MODE,
Expand Down
4 changes: 3 additions & 1 deletion .../apache/seatunnel/connectors/seatunnel/cdc/mysql/source/eumerator/MySqlChunkSplitter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -28,10 +28,12 @@
import io.debezium.jdbc.JdbcConnection;
import io.debezium.relational.Column;
import io.debezium.relational.TableId;
import lombok.extern.slf4j.Slf4j;

import java.sql.SQLException;

/** The {@code ChunkSplitter} used to split table into a set of chunks for JDBC data source. */
@Slf4j
public class MySqlChunkSplitter extends AbstractJdbcSourceChunkSplitter {

public MySqlChunkSplitter(JdbcSourceConfig sourceConfig, JdbcDataSourceDialect dialect) {
Expand All @@ -55,7 +57,7 @@ public Object queryMin(
public Object[] sampleDataFromColumn(
JdbcConnection jdbc, TableId tableId, String columnName, int inverseSamplingRate)
throws SQLException {
return MySqlUtils.sampleDataFromColumn(jdbc, tableId, columnName, inverseSamplingRate);
return MySqlUtils.skipReadAndSortSampleData(jdbc, tableId, columnName, inverseSamplingRate);
}

@Override
Expand Down
53 changes: 53 additions & 0 deletions ...l/src/main/java/org/apache/seatunnel/connectors/seatunnel/cdc/mysql/utils/MySqlUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -36,11 +36,13 @@
import io.debezium.relational.TableId;
import io.debezium.schema.TopicSelector;
import io.debezium.util.SchemaNameAdjuster;
import lombok.extern.slf4j.Slf4j;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
Expand All @@ -52,6 +54,7 @@
import static org.apache.seatunnel.connectors.cdc.base.utils.SourceRecordUtils.rowToArray;

/** Utils to prepare MySQL SQL statement. */
@Slf4j
public class MySqlUtils {

private MySqlUtils() {}
Expand Down Expand Up @@ -142,6 +145,56 @@ public static Object[] sampleDataFromColumn(
});
}

public static Object[] skipReadAndSortSampleData(
JdbcConnection jdbc, TableId tableId, String columnName, int inverseSamplingRate)
throws SQLException {
final String sampleQuery =
String.format("SELECT %s FROM %s", quote(columnName), quote(tableId));

Statement stmt = null;
ResultSet rs = null;

List<Object> results = new ArrayList<>();
try {
stmt =
jdbc.connection()
.createStatement(
ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);

stmt.setFetchSize(Integer.MIN_VALUE);
rs = stmt.executeQuery(sampleQuery);

int count = 0;
while (rs.next()) {
count++;
if (count % 100000 == 0) {
log.info("Processing row index: {}", count);
}
if (count % inverseSamplingRate == 0) {
results.add(rs.getObject(1));
}
}
} finally {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
log.error("Failed to close ResultSet", e);
}
}
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
log.error("Failed to close Statement", e);
}
}
}
Object[] resultsArray = results.toArray();
Arrays.sort(resultsArray);
return resultsArray;
}

public static Object queryNextChunkMax(
JdbcConnection jdbc,
TableId tableId,
Expand Down
3 changes: 2 additions & 1 deletion ...el/connectors/seatunnel/cdc/sqlserver/source/source/eumerator/SqlServerChunkSplitter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -57,7 +57,8 @@ public Object queryMin(
public Object[] sampleDataFromColumn(
JdbcConnection jdbc, TableId tableId, String columnName, int inverseSamplingRate)
throws SQLException {
return SqlServerUtils.sampleDataFromColumn(jdbc, tableId, columnName, inverseSamplingRate);
return SqlServerUtils.skipReadAndSortSampleData(
jdbc, tableId, columnName, inverseSamplingRate);
}

@Override
Expand Down
54 changes: 54 additions & 0 deletions .../org/apache/seatunnel/connectors/seatunnel/cdc/sqlserver/source/utils/SqlServerUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,10 +39,13 @@
import io.debezium.relational.TableId;
import io.debezium.schema.TopicSelector;
import io.debezium.util.SchemaNameAdjuster;
import lombok.extern.slf4j.Slf4j;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
Expand All @@ -52,6 +55,7 @@
import java.util.Optional;

/** The utils for SqlServer data source. */
@Slf4j
public class SqlServerUtils {

public SqlServerUtils() {}
Expand Down Expand Up @@ -145,6 +149,56 @@ public static Object[] sampleDataFromColumn(
});
}

public static Object[] skipReadAndSortSampleData(
JdbcConnection jdbc, TableId tableId, String columnName, int inverseSamplingRate)
throws SQLException {
final String sampleQuery =
String.format("SELECT %s FROM %s", quote(columnName), quote(tableId));

Statement stmt = null;
ResultSet rs = null;

List<Object> results = new ArrayList<>();
try {
stmt =
jdbc.connection()
.createStatement(
ResultSet.TYPE_FORWARD_ONLY, ResultSet.CONCUR_READ_ONLY);

stmt.setFetchSize(Integer.MIN_VALUE);
rs = stmt.executeQuery(sampleQuery);

int count = 0;
while (rs.next()) {
count++;
if (count % 100000 == 0) {
log.info("Processing row index: {}", count);
}
if (count % inverseSamplingRate == 0) {
results.add(rs.getObject(1));
}
}
} finally {
if (rs != null) {
try {
rs.close();
} catch (SQLException e) {
log.error("Failed to close ResultSet", e);
}
}
if (stmt != null) {
try {
stmt.close();
} catch (SQLException e) {
log.error("Failed to close Statement", e);
}
}
}
Object[] resultsArray = results.toArray();
Arrays.sort(resultsArray);
return resultsArray;
}

/**
* Returns the next LSN to be read from the database. This is the LSN of the last record that
* was read from the database.
Expand Down
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