From a61a4d4034eac5d33b737ef330a940ade0cbce7a Mon Sep 17 00:00:00 2001
From: morningman <yunyou@selectdb.com>
Date: Sun, 8 Dec 2024 12:56:33 -0800
Subject: [PATCH] table level row count

---
 .../iceberg/source/IcebergScanNode.java        | 18 ++++++++++++------
 .../iceberg/source/IcebergSplit.java           | 11 ++---------
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergScanNode.java b/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergScanNode.java
index efcd646b873b2ae..c78140b9d3cd995 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergScanNode.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergScanNode.java
@@ -87,7 +87,13 @@ public class IcebergScanNode extends FileQueryScanNode {
     private IcebergSource source;
     private Table icebergTable;
     private List<String> pushdownIcebergPredicates = Lists.newArrayList();
-    private boolean pushDownCount = false;
+    // If tableLevelPushDownCount is true, means we can do count push down opt at table level.
+    // which means all splits have no position/equality delete files,
+    // so for query like "select count(*) from ice_tbl", we can get count from snapshot row count info directly.
+    // If tableLevelPushDownCount is false, means we can't do count push down opt at table level,
+    // But for part of splits which have no position/equality delete files, we can still do count push down opt.
+    // And for split level count push down opt, the flag is set in each split.
+    private boolean tableLevelPushDownCount = false;
     private static final long COUNT_WITH_PARALLEL_SPLITS = 10000;
 
     /**
@@ -140,8 +146,8 @@ private void setIcebergParams(TFileRangeDesc rangeDesc, IcebergSplit icebergSpli
         int formatVersion = icebergSplit.getFormatVersion();
         fileDesc.setFormatVersion(formatVersion);
         fileDesc.setOriginalFilePath(icebergSplit.getOriginalPath());
-        if (pushDownCount) {
-            fileDesc.setRowCount(icebergSplit.getRowCount());
+        if (tableLevelPushDownCount) {
+            fileDesc.setRowCount(icebergSplit.getTableLevelRowCount());
         }
         if (formatVersion < MIN_DELETE_FILE_SUPPORT_VERSION) {
             fileDesc.setContent(FileContent.DATA.id());
@@ -271,7 +277,7 @@ private List<Split> doGetSplits(int numBackends) throws UserException {
             }
             long countFromSnapshot = getCountFromSnapshot();
             if (countFromSnapshot >= 0) {
-                pushDownCount = true;
+                tableLevelPushDownCount = true;
                 List<Split> pushDownCountSplits;
                 if (countFromSnapshot > COUNT_WITH_PARALLEL_SPLITS) {
                     int minSplits = sessionVariable.getParallelExecInstanceNum() * numBackends;
@@ -424,8 +430,8 @@ private void assignCountToSplits(List<Split> splits, long totalCount) {
         int size = splits.size();
         long countPerSplit = totalCount / size;
         for (int i = 0; i < size - 1; i++) {
-            ((IcebergSplit) splits.get(i)).setRowCount(countPerSplit);
+            ((IcebergSplit) splits.get(i)).setTableLevelRowCount(countPerSplit);
         }
-        ((IcebergSplit) splits.get(size - 1)).setRowCount(countPerSplit + totalCount % size);
+        ((IcebergSplit) splits.get(size - 1)).setTableLevelRowCount(countPerSplit + totalCount % size);
     }
 }
diff --git a/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergSplit.java b/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergSplit.java
index 580d3cf1bb23f38..0520612935a7781 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergSplit.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/datasource/iceberg/source/IcebergSplit.java
@@ -37,7 +37,8 @@ public class IcebergSplit extends FileSplit {
     private Integer formatVersion;
     private List<IcebergDeleteFileFilter> deleteFileFilters;
     private Map<String, String> config;
-    private long rowCount = -1;
+    // tableLevelRowCount will be set only table-level count push down opt is available.
+    private long tableLevelRowCount = -1;
 
     // File path will be changed if the file is modified, so there's no need to get modification time.
     public IcebergSplit(LocationPath file, long start, long length, long fileLength, String[] hosts,
@@ -50,14 +51,6 @@ public IcebergSplit(LocationPath file, long start, long length, long fileLength,
         this.selfSplitWeight = length;
     }
 
-    public long getRowCount() {
-        return rowCount;
-    }
-
-    public void setRowCount(long rowCount) {
-        this.rowCount = rowCount;
-    }
-
     public void setDeleteFileFilters(List<IcebergDeleteFileFilter> deleteFileFilters) {
         this.deleteFileFilters = deleteFileFilters;
         this.selfSplitWeight += deleteFileFilters.stream().mapToLong(IcebergDeleteFileFilter::getFilesize).sum();