[FDC] Fix the transaction hang bug with pglite (#9771)

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Author: fredzqm

CHANGELOG.md

@@ -0,0 +1 @@
+- Fix the bug when Data Connect emulator hangs with PGlite. (Issue #9756) #9771

src/emulator/dataconnectEmulator.ts

@@ -333,7 +333,9 @@ export class DataConnectEmulator implements EmulatorInstance {
           connectionString: connectionString.toString(),
           database,
           serviceId,
-          maxOpenConnections: 1, // PGlite only supports a single open connection at a time - otherwise, prepared statements will misbehave.
+          // NOTE: Previously, we set `maxOpenConnections: 1` to get around PGlite's limitation with prepared statements.
+          // Since we switched emulator to avoid prepared statement, multiple connections are OK.
+          // Transactional operations (`mutation @transaction`) actually requires multiple connections.
         });
         this.logger.logLabeled(
           "DEBUG",