From 3d0eec020bd8ef4bf3217441d2c49346a9bbc198 Mon Sep 17 00:00:00 2001
From: Trisha Anand <trisha@appsmith.com>
Date: Tue, 2 Apr 2024 20:20:51 +0530
Subject: [PATCH] fix: Scheduling synchronized block on bounded elastic
 threadpool instead of main event threadpool (#32343)
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…

## Description
> [!TIP]
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extremely technical (helps the content team)._
>
> _Please also include relevant motivation and context. List any
dependencies that are required for this change. Add links to Notion,
Figma or any other documents that might be relevant to the PR._

Fixes #`Issue Number`
_or_
Fixes `Issue URL`
> [!WARNING]
> _If no issue exists, please create an issue first, and check with the
maintainers if the issue is valid._

## Automation

/ok-to-test tags="@tag.Sanity"

### :mag: Cypress test results
<!-- This is an auto-generated comment: Cypress test results  -->
> [!IMPORTANT]
> Workflow run:
<https://github.com/appsmithorg/appsmith/actions/runs/8523943321>
> Commit: `03dc817039ee24159438e613320550620353a2b7`
> Cypress dashboard url: <a
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit


- **Refactor**
- Improved backend scheduling for datasource operations to enhance
performance without blocking the main thread.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->
---
 .../ce/DatasourceContextServiceCEImpl.java        | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/DatasourceContextServiceCEImpl.java b/app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/DatasourceContextServiceCEImpl.java
index 3fa73f2f2ac..10041855726 100644
--- a/app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/DatasourceContextServiceCEImpl.java
+++ b/app/server/appsmith-server/src/main/java/com/appsmith/server/services/ce/DatasourceContextServiceCEImpl.java
@@ -24,6 +24,7 @@
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.context.annotation.Lazy;
 import reactor.core.publisher.Mono;
+import reactor.core.scheduler.Schedulers;
 
 import java.time.Instant;
 import java.util.Map;
@@ -103,7 +104,8 @@ public Mono<? extends DatasourceContext<?>> getCachedDatasourceContextMono(
                         // Basically remove entry from both cache maps
                         pluginExecutor.datasourceDestroy(connection);
                     } catch (Exception e) {
-                        log.info("Error destroying stale datasource connection", e);
+                        log.info(
+                                Thread.currentThread().getName() + ": Error destroying stale datasource connection", e);
                     }
                 }
                 datasourceContextMonoMap.remove(datasourceContextIdentifier);
@@ -117,7 +119,8 @@ public Mono<? extends DatasourceContext<?>> getCachedDatasourceContextMono(
              */
             if (datasourceContextIdentifier.getDatasourceId() != null
                     && datasourceContextMonoMap.get(datasourceContextIdentifier) != null) {
-                log.debug("Cached resource context mono exists. Returning the same.");
+                log.debug(Thread.currentThread().getName()
+                        + ": Cached resource context mono exists. Returning the same.");
                 return datasourceContextMonoMap.get(datasourceContextIdentifier);
             }
 
@@ -182,11 +185,11 @@ public Mono<Object> updateDatasourceAndSetAuthentication(Object connection, Data
 
     protected Mono<DatasourceContext<?>> createNewDatasourceContext(
             DatasourceStorage datasourceStorage, DatasourceContextIdentifier datasourceContextIdentifier) {
-        log.debug("Datasource context doesn't exist. Creating connection.");
+        log.debug(Thread.currentThread().getName() + ": Datasource context doesn't exist. Creating connection.");
         Mono<Plugin> pluginMono =
                 pluginService.findById(datasourceStorage.getPluginId()).cache();
 
-        return pluginMono
+        return (Mono<DatasourceContext<?>>) pluginMono
                 .zipWith(pluginExecutorHelper.getPluginExecutor(pluginMono))
                 .flatMap(tuple2 -> {
                     Plugin plugin = tuple2.getT1();
@@ -214,7 +217,9 @@ protected Mono<DatasourceContext<?>> createNewDatasourceContext(
 
                     return getCachedDatasourceContextMono(
                             datasourceStorage, plugin, pluginExecutor, monitor, datasourceContextIdentifier);
-                });
+                })
+                // Scheduling on bounded elastic to avoid blocking the main thread
+                .subscribeOn(Schedulers.boundedElastic());
     }
 
     public boolean getIsStale(