HADOOP-19622. [3.4 Backport][ABFS][ReadAheadV2] Implement Read Buffer Manager V2 with improved aggressiveness

[anujmodi2021]

Description of PR

JIRA: https://issues.apache.org/jira/browse/HADOOP-19622

Implementing ReadBufferManagerV2 as per the new design document.
Following capabilities are added to ReadBufferManager:

1. Configurable minimum and maximum number of prefetch threads.
2. Configurable minimum and maximum size of cached buffer pool
3. Dynamically adjusting thread pool size and buffer pool size based on workload requirement and resource utilization but within the limits defined by user.
4. Mapping prefetched data to file ETag so that multiple streams reading same file can share the cache and save TPS.

For more details on design doc please refer to the design doc attached to parent JIRA: https://issues.apache.org/jira/browse/HADOOP-19596

How was this patch tested?

New tests added and existing test suite ran

[hadoop-yetus]

🎊 +1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	0m 48s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+0 🆗	detsecrets	0m 0s		detect-secrets was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 10 new or modified test files.
			_ branch-3.4 Compile Tests _
+1 💚	mvninstall	23m 47s		branch-3.4 passed
+1 💚	compile	0m 21s		branch-3.4 passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	compile	0m 19s		branch-3.4 passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	checkstyle	0m 18s		branch-3.4 passed
+1 💚	mvnsite	0m 24s		branch-3.4 passed
+1 💚	javadoc	0m 21s		branch-3.4 passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 20s		branch-3.4 passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	0m 43s		branch-3.4 passed
+1 💚	shadedclient	19m 10s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 17s		the patch passed
+1 💚	compile	0m 19s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javac	0m 19s		the patch passed
+1 💚	compile	0m 16s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	javac	0m 16s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
-0 ⚠️	checkstyle	0m 11s	/results-checkstyle-hadoop-tools_hadoop-azure.txt	hadoop-tools/hadoop-azure: The patch generated 1 new + 5 unchanged - 9 fixed = 6 total (was 14)
+1 💚	mvnsite	0m 18s		the patch passed
+1 💚	javadoc	0m 16s		the patch passed with JDK Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04
+1 💚	javadoc	0m 19s		the patch passed with JDK Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
+1 💚	spotbugs	0m 43s		the patch passed
+1 💚	shadedclient	18m 51s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	2m 4s		hadoop-azure in the patch passed.
+1 💚	asflicense	0m 25s		The patch does not generate ASF License warnings.
		72m 16s

Subsystem	Report/Notes
Docker	ClientAPI=1.52 ServerAPI=1.52 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8175/1/artifact/out/Dockerfile
GITHUB PR	#8175
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell detsecrets
uname	Linux 5c24df522570 5.15.0-164-generic #174-Ubuntu SMP Fri Nov 14 20:25:16 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	branch-3.4 / f84683c
Default Java	Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.27+6-post-Ubuntu-0ubuntu120.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_452-8u452-gaus1-0ubuntu120.04-b09
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8175/1/testReport/
Max. process+thread count	552 (vs. ulimit of 5500)
modules	C: hadoop-tools/hadoop-azure U: hadoop-tools/hadoop-azure
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-8175/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[anujmodi2021]

---

:::: AGGREGATED TEST RESULT ::::

============================================================
HNS-OAuth-DFS

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 3
[WARNING] Tests run: 888, Failures: 0, Errors: 0, Skipped: 231
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 32
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 23

============================================================
HNS-SharedKey-DFS

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 4
[WARNING] Tests run: 888, Failures: 0, Errors: 0, Skipped: 180
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 32
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 10

============================================================
NonHNS-SharedKey-DFS

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 437
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 33
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 11

============================================================
AppendBlob-HNS-OAuth-DFS

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 3
[WARNING] Tests run: 888, Failures: 0, Errors: 0, Skipped: 242
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 56
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 23

============================================================
NonHNS-SharedKey-Blob

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 288
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 27
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 11

============================================================
NonHNS-OAuth-DFS

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 442
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 33
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 24

============================================================
NonHNS-OAuth-Blob

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 303
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 27
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 24

============================================================
AppendBlob-NonHNS-OAuth-Blob

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 354
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 51
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 24

============================================================
HNS-Oauth-DFS-IngressBlob

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 3
[WARNING] Tests run: 888, Failures: 0, Errors: 0, Skipped: 366
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 32
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 23

============================================================
NonHNS-OAuth-DFS-IngressBlob

[WARNING] Tests run: 186, Failures: 0, Errors: 0, Skipped: 10
[WARNING] Tests run: 872, Failures: 0, Errors: 0, Skipped: 439
[WARNING] Tests run: 182, Failures: 0, Errors: 0, Skipped: 33
[WARNING] Tests run: 274, Failures: 0, Errors: 0, Skipped: 24

[anujmodi2021]

@steveloughran, wanted to check with you if its okay to go ahead with this merge to 3.4?
Or are we not accepting any new changes for 3.4.3 release?

[anujmodi2021]

Since this change is already behind a config, disabled by default, I am goign ahead with the merge to 3.4.