[ASTERIXDB-3314][STO] Reduce buffer cache pressure on columnar

- user model changes: no
- storage format changes: no
- interface changes: no

Details:
- Make max merging components count to 4 in columnar datasets
- Fix not unpinning columnar filter pages
- Allocate initial 32KB buffers for columnar writers

Change-Id: I809109b232bc5a5db0c47a52cb98c838ff55e27f
Reviewed-on: https://asterix-gerrit.ics.uci.edu/c/asterixdb/+/17965
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Murtadha Hubail <mhubail@apache.org>
diff --git a/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-btree-column/pom.xml b/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-btree-column/pom.xml
index 8e0bc0c..93eca7c 100644
--- a/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-btree-column/pom.xml
+++ b/hyracks-fullstack/hyracks/hyracks-storage-am-lsm-btree-column/pom.xml
@@ -95,5 +95,9 @@
       <groupId>com.fasterxml.jackson.core</groupId>
       <artifactId>jackson-databind</artifactId>
     </dependency>
+    <dependency>
+      <groupId>it.unimi.dsi</groupId>
+      <artifactId>fastutil-core</artifactId>
+    </dependency>
   </dependencies>
 </project>