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Posted to commits@doris.apache.org by kx...@apache.org on 2023/11/03 15:35:54 UTC
(doris) branch branch-2.0 updated: [fix](planner) Fix sample partition table #25912 (#26399)
This is an automated email from the ASF dual-hosted git repository.
kxiao pushed a commit to branch branch-2.0
in repository https://gitbox.apache.org/repos/asf/doris.git
The following commit(s) were added to refs/heads/branch-2.0 by this push:
new fb75f1253bf [fix](planner) Fix sample partition table #25912 (#26399)
fb75f1253bf is described below
commit fb75f1253bf91b46176cd506d3bee74478f93375
Author: Xinyi Zou <zo...@gmail.com>
AuthorDate: Fri Nov 3 23:35:47 2023 +0800
[fix](planner) Fix sample partition table #25912 (#26399)
In the past, two conditions needed to be met when sampling a partitioned table: 1. Data is evenly distributed between partitions; 2. Data is evenly distributed between buckets. Finally, the number of sampled rows in each partition and each bucket is the same.
Now, sampling will be proportional to the number of partitioned and bucketed rows.
---
.../glue/translator/PhysicalPlanTranslator.java | 2 +-
.../org/apache/doris/planner/OlapScanNode.java | 130 ++++++++++++---------
.../org/apache/doris/analysis/SelectStmtTest.java | 9 +-
3 files changed, 83 insertions(+), 58 deletions(-)
diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
index e2bdf6b92fd..3da1e9917bf 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
@@ -611,7 +611,7 @@ public class PhysicalPlanTranslator extends DefaultPlanVisitor<PlanFragment, Pla
BaseTableRef tableRef = new BaseTableRef(ref, olapTable, tableName);
tupleDescriptor.setRef(tableRef);
olapScanNode.setSelectedPartitionIds(olapScan.getSelectedPartitionIds());
- olapScanNode.setSampleTabletIds(olapScan.getSelectedTabletIds());
+ olapScanNode.setSampleTabletIds(olapScan.getSelectedTabletIds()); // TODO
if (olapScan.getTableSample().isPresent()) {
olapScanNode.setTableSample(new TableSample(olapScan.getTableSample().get().isPercent,
olapScan.getTableSample().get().sampleValue, olapScan.getTableSample().get().seek));
diff --git a/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java b/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
index 98490369f03..5c85baca318 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/planner/OlapScanNode.java
@@ -59,6 +59,7 @@ import org.apache.doris.common.AnalysisException;
import org.apache.doris.common.Config;
import org.apache.doris.common.ErrorCode;
import org.apache.doris.common.ErrorReport;
+import org.apache.doris.common.FeConstants;
import org.apache.doris.common.UserException;
import org.apache.doris.common.util.Util;
import org.apache.doris.nereids.glue.translator.PlanTranslatorContext;
@@ -94,9 +95,11 @@ import com.google.common.collect.Sets;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
+import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
+import java.util.Comparator;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
@@ -219,7 +222,7 @@ public class OlapScanNode extends ScanNode {
public void setIsPreAggregation(boolean isPreAggregation, String reason) {
this.isPreAggregation = isPreAggregation;
this.reasonOfPreAggregation = this.reasonOfPreAggregation == null ? reason :
- this.reasonOfPreAggregation + " " + reason;
+ this.reasonOfPreAggregation + " " + reason;
}
@@ -401,7 +404,8 @@ public class OlapScanNode extends ScanNode {
String scanRangeInfo = stringBuilder.toString();
String situation;
boolean update;
- CHECK: { // CHECKSTYLE IGNORE THIS LINE
+ CHECK:
+ { // CHECKSTYLE IGNORE THIS LINE
if (olapTable.getKeysType() == KeysType.DUP_KEYS || (olapTable.getKeysType() == KeysType.UNIQUE_KEYS
&& olapTable.getEnableUniqueKeyMergeOnWrite())) {
situation = "The key type of table is duplicate, or unique key with merge-on-write.";
@@ -773,7 +777,7 @@ public class OlapScanNode extends ScanNode {
// but it means we will do 3 S3 IO to get the data which will bring 3 slow query
if (-1L != coolDownReplicaId) {
final Optional<Replica> replicaOptional = replicas.stream()
- .filter(r -> r.getId() == coolDownReplicaId).findAny();
+ .filter(r -> r.getId() == coolDownReplicaId).findAny();
replicaOptional.ifPresent(
r -> {
Backend backend = Env.getCurrentSystemInfo()
@@ -925,75 +929,91 @@ public class OlapScanNode extends ScanNode {
}
/**
- * First, determine how many rows to sample from each partition according to the number of partitions.
- * Then determine the number of Tablets to be selected for each partition according to the average number
- * of rows of Tablet,
- * If seek is not specified, the specified number of Tablets are pseudo-randomly selected from each partition.
- * If seek is specified, it will be selected sequentially from the seek tablet of the partition.
- * And add the manually specified Tablet id to the selected Tablet.
- * simpleTabletNums = simpleRows / partitionNums / (partitionRows / partitionTabletNums)
+ * Sample some tablets in the selected partition.
+ * If Seek is specified, the tablets sampled each time are the same.
*/
public void computeSampleTabletIds() {
if (tableSample == null) {
return;
}
OlapTable olapTable = (OlapTable) desc.getTable();
- long sampleRows; // The total number of sample rows
- long hitRows = 1; // The total number of rows hit by the tablet
- long totalRows = 0; // The total number of partition rows hit
- long totalTablet = 0; // The total number of tablets in the hit partition
+
+ // 1. Calculate the total number of rows in the selected partition, and sort partition list.
+ long selectedRows = 0;
+ long totalSampleRows = 0;
+ List<Long> selectedPartitionList = new ArrayList<>();
+ if (FeConstants.runningUnitTest && selectedIndexId == -1) {
+ selectedIndexId = olapTable.getBaseIndexId();
+ }
+ for (Long partitionId : selectedPartitionIds) {
+ final Partition partition = olapTable.getPartition(partitionId);
+ final MaterializedIndex selectedTable = partition.getIndex(selectedIndexId);
+ selectedRows += selectedTable.getRowCount();
+ selectedPartitionList.add(partitionId);
+ }
+ selectedPartitionList.sort(Comparator.naturalOrder());
+
+ // 2.Sampling is not required in some cases, will not take effect after clear sampleTabletIds.
if (tableSample.isPercent()) {
- sampleRows = (long) Math.max(olapTable.getRowCount() * (tableSample.getSampleValue() / 100.0), 1);
+ if (tableSample.getSampleValue() >= 100) {
+ return;
+ }
+ totalSampleRows = (long) Math.max(selectedRows * (tableSample.getSampleValue() / 100.0), 1);
} else {
- sampleRows = Math.max(tableSample.getSampleValue(), 1);
+ if (tableSample.getSampleValue() > selectedRows) {
+ return;
+ }
+ totalSampleRows = tableSample.getSampleValue();
}
- // calculate the number of tablets by each partition
- long avgRowsPerPartition = sampleRows / Math.max(olapTable.getPartitions().size(), 1);
-
- for (Partition p : olapTable.getPartitions()) {
- List<Long> ids = p.getBaseIndex().getTabletIdsInOrder();
-
- if (ids.isEmpty()) {
+ // 3. Sampling partition. If Seek is specified, the partition will be the same for each sampling.
+ long hitRows = 0; // The number of rows hit by the tablet
+ long partitionSeek = tableSample.getSeek() != -1
+ ? tableSample.getSeek() : (long) (new SecureRandom().nextDouble() * selectedPartitionIds.size());
+ for (int i = 0; i < selectedPartitionList.size(); i++) {
+ int seekPid = (int) ((i + partitionSeek) % selectedPartitionList.size());
+ final Partition partition = olapTable.getPartition(selectedPartitionList.get(seekPid));
+ final MaterializedIndex selectedTable = partition.getIndex(selectedIndexId);
+ List<Tablet> tablets = selectedTable.getTablets();
+ if (tablets.isEmpty()) {
continue;
}
- // Skip partitions with row count < row count / 2 expected to be sampled per partition.
- // It can be expected to sample a smaller number of partitions to avoid uneven distribution
- // of sampling results.
- if (p.getBaseIndex().getRowCount() < (avgRowsPerPartition / 2)) {
- continue;
+ // 4. Calculate the number of rows that need to be sampled in the current partition.
+ long sampleRows = 0; // The number of sample rows in partition
+ if (tableSample.isPercent()) {
+ sampleRows = (long) Math.max(selectedTable.getRowCount() * (tableSample.getSampleValue() / 100.0), 1);
+ } else {
+ sampleRows = (long) Math.max(
+ tableSample.getSampleValue() * (selectedTable.getRowCount() / selectedRows), 1);
}
- // It is assumed here that all tablets row count is uniformly distributed
- // TODO Use `p.getBaseIndex().getTablet(n).getRowCount()` to get each tablet row count to compute sample.
- long avgRowsPerTablet = Math.max(p.getBaseIndex().getRowCount() / ids.size(), 1);
- long tabletCounts = Math.max(
- avgRowsPerPartition / avgRowsPerTablet + (avgRowsPerPartition % avgRowsPerTablet != 0 ? 1 : 0), 1);
- tabletCounts = Math.min(tabletCounts, ids.size());
-
- long seek = tableSample.getSeek() != -1
- ? tableSample.getSeek() : (long) (Math.random() * ids.size());
- for (int i = 0; i < tabletCounts; i++) {
- int seekTid = (int) ((i + seek) % ids.size());
- sampleTabletIds.add(ids.get(seekTid));
+ // 5. Sampling tablets. If Seek is specified, the same tablet will be sampled each time.
+ long tabletSeek = tableSample.getSeek() != -1
+ ? tableSample.getSeek() : (long) (new SecureRandom().nextDouble() * tablets.size());
+ for (int j = 0; j < tablets.size(); j++) {
+ int seekTid = (int) ((j + tabletSeek) % tablets.size());
+ long tabletRowCount;
+ if (!FeConstants.runningUnitTest) {
+ tabletRowCount = tablets.get(seekTid).getRowCount(true);
+ } else {
+ tabletRowCount = selectedTable.getRowCount() / tablets.size();
+ }
+ if (tabletRowCount == 0) {
+ continue;
+ }
+ sampleTabletIds.add(tablets.get(seekTid).getId());
+ sampleRows -= tabletRowCount;
+ hitRows += tabletRowCount;
+ if (sampleRows <= 0) {
+ break;
+ }
+ }
+ if (hitRows > totalSampleRows) {
+ break;
}
-
- hitRows += avgRowsPerTablet * tabletCounts;
- totalRows += p.getBaseIndex().getRowCount();
- totalTablet += ids.size();
- }
-
- // all hit, direct full
- if (totalRows < sampleRows) {
- // can't fill full sample rows
- sampleTabletIds.clear();
- } else if (sampleTabletIds.size() == totalTablet) {
- // TODO add limit
- sampleTabletIds.clear();
- } else if (!sampleTabletIds.isEmpty()) {
- // TODO add limit
}
+ LOG.debug("after computeSampleTabletIds, hitRows {}, selectedRows {}", hitRows, selectedRows);
}
public boolean isFromPrepareStmt() {
diff --git a/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java b/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java
index 33c47f6bf41..78f330eef6d 100755
--- a/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/analysis/SelectStmtTest.java
@@ -26,6 +26,7 @@ import org.apache.doris.catalog.Partition;
import org.apache.doris.catalog.Tablet;
import org.apache.doris.common.AnalysisException;
import org.apache.doris.common.Config;
+import org.apache.doris.common.FeConstants;
import org.apache.doris.common.util.Util;
import org.apache.doris.planner.OlapScanNode;
import org.apache.doris.planner.OriginalPlanner;
@@ -862,6 +863,7 @@ public class SelectStmtTest {
@Test
public void testSelectSampleHashBucketTable() throws Exception {
+ FeConstants.runningUnitTest = true;
Database db = Env.getCurrentInternalCatalog().getDbOrMetaException("default_cluster:db1");
OlapTable tbl = (OlapTable) db.getTableOrMetaException("table1");
long tabletId = 10031L;
@@ -894,7 +896,7 @@ public class SelectStmtTest {
String sql4 = "SELECT * FROM db1.table1 TABLESAMPLE(9500 ROWS)";
OriginalPlanner planner4 = (OriginalPlanner) dorisAssert.query(sql4).internalExecuteOneAndGetPlan();
Set<Long> sampleTabletIds4 = ((OlapScanNode) planner4.getScanNodes().get(0)).getSampleTabletIds();
- Assert.assertEquals(0, sampleTabletIds4.size()); // no sample, all tablet
+ Assert.assertEquals(10, sampleTabletIds4.size());
String sql5 = "SELECT * FROM db1.table1 TABLESAMPLE(11000 ROWS)";
OriginalPlanner planner5 = (OriginalPlanner) dorisAssert.query(sql5).internalExecuteOneAndGetPlan();
@@ -963,10 +965,12 @@ public class SelectStmtTest {
OriginalPlanner planner16 = (OriginalPlanner) dorisAssert.query(sql16).internalExecuteOneAndGetPlan();
Set<Long> sampleTabletIds16 = ((OlapScanNode) planner16.getScanNodes().get(0)).getSampleTabletIds();
Assert.assertEquals(1, sampleTabletIds16.size());
+ FeConstants.runningUnitTest = false;
}
@Test
public void testSelectSampleRandomBucketTable() throws Exception {
+ FeConstants.runningUnitTest = true;
Database db = Env.getCurrentInternalCatalog().getDbOrMetaException("default_cluster:db1");
OlapTable tbl = (OlapTable) db.getTableOrMetaException("table3");
long tabletId = 10031L;
@@ -999,7 +1003,7 @@ public class SelectStmtTest {
String sql4 = "SELECT * FROM db1.table3 TABLESAMPLE(9500 ROWS)";
OriginalPlanner planner4 = (OriginalPlanner) dorisAssert.query(sql4).internalExecuteOneAndGetPlan();
Set<Long> sampleTabletIds4 = ((OlapScanNode) planner4.getScanNodes().get(0)).getSampleTabletIds();
- Assert.assertEquals(0, sampleTabletIds4.size()); // no sample, all tablet
+ Assert.assertEquals(10, sampleTabletIds4.size());
String sql5 = "SELECT * FROM db1.table3 TABLESAMPLE(11000 ROWS)";
OriginalPlanner planner5 = (OriginalPlanner) dorisAssert.query(sql5).internalExecuteOneAndGetPlan();
@@ -1068,6 +1072,7 @@ public class SelectStmtTest {
OriginalPlanner planner16 = (OriginalPlanner) dorisAssert.query(sql16).internalExecuteOneAndGetPlan();
Set<Long> sampleTabletIds16 = ((OlapScanNode) planner16.getScanNodes().get(0)).getSampleTabletIds();
Assert.assertEquals(1, sampleTabletIds16.size());
+ FeConstants.runningUnitTest = false;
}
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