Remove the Summary Cache (#12036)

The Powerapp would have a latency issue on FRS, since the client would
open the new session from the Storage every time, instead of using the
cache. We would enable the cache, in this case, to speed up the process.

server/historian/packages/historian-base/src/services/restGitService.ts

@@ -239,7 +239,7 @@ export class RestGitService {
         return this.delete<boolean>(`/repos/${this.getRepoPath()}/git/summaries`, headers);
     }
 
-    public async getSummary(sha: string, useCache: boolean): Promise<IWholeFlatSummary> {
+    public async getSummary(sha: string, _useCache: boolean): Promise<IWholeFlatSummary> {
         const summaryFetch = async () => this.get<IWholeFlatSummary>(
             `/repos/${this.getRepoPath()}/git/summaries/${encodeURIComponent(sha)}`);
 
@@ -254,14 +254,17 @@ export class RestGitService {
         // the request.
         const summaryCacheKey = this.getSummaryCacheKey("container");
 
-        if (!useCache) {
-            // We set the useCache flag as false when we fetch the initial latest summary for a document.
-            // In that scenario, useCache as false means that we need to get the summary from storage and bypass the
-            // cache, since the cached data might be obsolete due to a cluster change. After fetching the value from
-            // storage, we add it to the cache so it can be up-to-date. As a result, subsequent requests that use
-            // the cache can read the correct value.
-            return this.fetchAndCache(summaryCacheKey, summaryFetch);
-        }
+        // To do: Right now, we enable the cache anytime. We will choose either one of the following options:
+        // 1. Always using the cache but clearing the cache at session end from the server.
+        // 2. The driver fix to disable cache only on session start or cluster change if we can detect it.
+        // if (!useCache) {
+        //     // We set the useCache flag as false when we fetch the initial latest summary for a document.
+        //     // In that scenario, useCache as false means that we need to get the summary from storage and bypass the
+        //     // cache, since the cached data might be obsolete due to a cluster change. After fetching the value from
+        //     // storage, we add it to the cache so it can be up-to-date. As a result, subsequent requests that use
+        //     // the cache can read the correct value.
+        //     return this.fetchAndCache(summaryCacheKey, summaryFetch);
+        // }
 
         // If we get to this point, we want to obtain the latest summary, and we want to try reading it from the cache.
         return this.resolve(summaryCacheKey, summaryFetch, true);