Merge pull request #221171 from AwdotiaRomanowna/patch-15

Update concepts-pgbouncer.md

Author: prmerger-automator[bot]

articles/postgresql/flexible-server/concepts-pgbouncer.md

@@ -92,6 +92,7 @@ Utilizing an application side pool together with PgBouncer on the database serve
 * If you change the compute tier from General Purpose or Memory Optimized to Burstable tier, you will lose the PgBouncer capability.
 * Whenever the server is restarted during scale operations, HA failover, or a restart, the PgBouncer is also restarted along with the server virtual machine. Hence the existing connections have to be re-established.
 * Due to a known issue, the portal does not show all PgBouncer parameters. Once you enable PgBouncer and save the parameter, you have to exit Parameter screen (for example, click Overview) and then get back to Parameters page. 
+* Transaction and statement pool modes cannnot be used along with prepared statements. Refer to the [PgBouncer documentation](https://www.pgbouncer.org/features.html) to check other limitations of chosen pool mode.
 
 
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