diff --git a/compactor/src/components/round_info_source/mod.rs b/compactor/src/components/round_info_source/mod.rs
index 83bcc9c586..c9afbd3e97 100644
--- a/compactor/src/components/round_info_source/mod.rs
+++ b/compactor/src/components/round_info_source/mod.rs
@@ -11,9 +11,9 @@ use crate::components::{
     Components,
 };
 use async_trait::async_trait;
-use data_types::{CompactionLevel, FileRange, ParquetFile, Timestamp};
+use data_types::{CompactionLevel, FileRange, ParquetFile, Timestamp, TransitionPartitionId};
 use itertools::Itertools;
-use observability_deps::tracing::debug;
+use observability_deps::tracing::{debug, info};
 
 use crate::{error::DynError, PartitionInfo, RoundInfo};
 
@@ -218,6 +218,7 @@ impl LevelBasedRoundInfo {
     /// If neither is returned, the caller will identify another type of RoundInfo for this round of compaction.
     pub fn vertical_split_handling(
         &self,
+        partition_id: TransitionPartitionId,
         files: Vec<ParquetFile>,
         max_compact_size: usize,
     ) -> (Vec<i64>, Vec<FileRange>) {
@@ -239,6 +240,12 @@ impl LevelBasedRoundInfo {
         for chain in &chains {
             let chain_cap: usize = chain.iter().map(|f| f.file_size_bytes as usize).sum();
 
+            if chain.len() > 300 && chain_cap / chain.len() < max_compact_size / 10 {
+                info!("skipping vertical splitting on partition_id {} for now, due to excessive file count.  chain length: {}, cap: {} MB",
+                    partition_id, chain.len(), chain_cap/1024/1024);
+                continue;
+            }
+
             // A single file over max size can just get upgraded to L1, then L2, unless it overlaps other L0s.
             // So multi file chains over the max compact size may need split
             if chain.len() > 1 && chain_cap > max_compact_size {
@@ -424,8 +431,11 @@ impl RoundInfoSource for LevelBasedRoundInfo {
                 max_total_file_size_to_group: self.max_total_file_size_per_plan,
             }
         } else if start_level == CompactionLevel::Initial {
-            let (split_times, ranges) = self
-                .vertical_split_handling(files.clone().to_vec(), self.max_total_file_size_per_plan);
+            let (split_times, ranges) = self.vertical_split_handling(
+                partition_info.partition_id(),
+                files.clone().to_vec(),
+                self.max_total_file_size_per_plan,
+            );
 
             if !split_times.is_empty() {
                 RoundInfo::VerticalSplit { split_times }
diff --git a/compactor/tests/layouts/many_files.rs b/compactor/tests/layouts/many_files.rs
index 599dc0a2b5..4dd6f768f7 100644
--- a/compactor/tests/layouts/many_files.rs
+++ b/compactor/tests/layouts/many_files.rs
@@ -5725,21 +5725,21 @@ async fn l0s_needing_vertical_split() {
     - "L0.998[24,100] 1.02us    |-----------------------------------------L0.998-----------------------------------------|"
     - "L0.999[24,100] 1.02us    |-----------------------------------------L0.999-----------------------------------------|"
     - "L0.1000[24,100] 1.02us   |----------------------------------------L0.1000-----------------------------------------|"
-    - "**** Final Output Files (2.63gb written)"
+    - "**** Final Output Files (2.62gb written)"
     - "L2                                                                                                                 "
-    - "L2.6026[24,34] 1.02us 107mb|-L2.6026-|                                                                               "
-    - "L2.6034[81,91] 1.02us 107mb                                                                   |-L2.6034-|            "
-    - "L2.6035[92,100] 1.02us 88mb                                                                                |L2.6035| "
-    - "L2.6036[35,45] 1.02us 107mb             |-L2.6036-|                                                                  "
-    - "L2.6037[46,55] 1.02us 97mb                          |L2.6037-|                                                      "
-    - "L2.6038[56,63] 1.02us 78mb                                     |L2.6038|                                            "
-    - "L2.6039[64,74] 1.02us 107mb                                               |-L2.6039-|                                "
-    - "L2.6040[75,80] 1.02us 58mb                                                            |L2.6040|                     "
+    - "L2.1018[24,34] 1.02us 107mb|-L2.1018-|                                                                               "
+    - "L2.1019[35,44] 1.02us 97mb             |L2.1019-|                                                                   "
+    - "L2.1020[45,50] 1.02us 58mb                        |L2.1020|                                                         "
+    - "L2.1021[51,61] 1.02us 107mb                               |-L2.1021-|                                                "
+    - "L2.1022[62,71] 1.02us 97mb                                             |L2.1022-|                                   "
+    - "L2.1027[72,82] 1.02us 107mb                                                        |-L2.1027-|                       "
+    - "L2.1028[83,92] 1.02us 97mb                                                                     |L2.1028-|           "
+    - "L2.1029[93,100] 1.02us 78mb                                                                                 |L2.1029|"
     - "**** Breakdown of where bytes were written"
-    - 282mb written by split(CompactAndSplitOutput(FoundSubsetLessThanMaxCompactSize))
-    - 750mb written by compact(ManySmallFiles)
-    - 750mb written by split(VerticalSplit)
-    - 916mb written by split(CompactAndSplitOutput(TotalSizeLessThanMaxCompactSize))
+    - 1.01gb written by split(CompactAndSplitOutput(TotalSizeLessThanMaxCompactSize))
+    - 300mb written by split(CompactAndSplitOutput(FoundSubsetLessThanMaxCompactSize))
+    - 450mb written by split(VerticalSplit)
+    - 899mb written by compact(ManySmallFiles)
     "###
     );
 }