[docs] [2.23] Add pg_cron extension docs

docs/content/preview/explore/ysql-language-features/pg-extensions/_index.md

@@ -59,6 +59,7 @@ YugabyteDB supports the following additional extensions, some of which you must
 | [HypoPG](extension-hypopg/) | Pre-bundled | Create hypothetical indexes to test whether an index can increase performance for problematic queries without consuming any actual resources. |
 | Orafce | Pre-bundled | Provides compatibility with Oracle functions and packages that are either missing or implemented differently in YugabyteDB and PostgreSQL. This compatibility layer can help you port your Oracle applications to YugabyteDB.<br/>For more information, see the [Orafce](https://github.com/orafce/orafce) documentation. |
 | [PGAudit](../../../secure/audit-logging/audit-logging-ysql/) | Pre-bundled | The PostgreSQL Audit Extension (pgaudit) provides detailed session and/or object audit logging via the standard PostgreSQL logging facility. |
+| [pg_cron](extension-pgcron/) | Pre-bundled | Provides a cron-based job scheduler that runs inside the database. |
 | [pg_hint_plan](../../query-1-performance/pg-hint-plan/#root) | Pre-bundled | Tweak execution plans using "hints", which are descriptions in the form of SQL comments.<br/>For more information, see the [pg_hint_plan](https://pghintplan.osdn.jp/pg_hint_plan.html) documentation. |
 | pg_stat_monitor | Pre-bundled | A PostgreSQL query performance monitoring tool, based on the PostgreSQL pg_stat_statements module.<br/>For more information, see the [pg_stat_monitor](https://docs.percona.com/pg-stat-monitor/index.html) documentation. |
 | [pgvector](extension-pgvector) | Pre-bundled | Allows you to store and query vectors, for use in vector similarity searching. |

docs/content/preview/explore/ysql-language-features/pg-extensions/extension-pgcron.md

@@ -0,0 +1,35 @@
+---
+title: pg_cron extension
+headerTitle: pg_cron extension
+linkTitle: pg_cron
+description: Using the pg_cron extension in YugabyteDB
+techPreview: /preview/releases/versioning/#feature-availability
+menu:
+  preview:
+    identifier: extension-pgcron
+    parent: pg-extensions
+    weight: 20
+type: docs
+---
+
+The [pg_cron](https://github.com/citusdata/pg_cron) extension provides a cron-based job scheduler that runs inside the database. It uses the same syntax as regular cron, and allows you to schedule YSQL commands directly from the database. You can also use '[1-59] seconds' to schedule a job based on an interval.
+
+## Enable pg_cron
+
+As pg_cron is in tech preview, you must first enable the feature by setting the `enable_pg_cron` preview flag to true, and adding it to the `allowed_preview_flags_csv` flag, for both YB-Master and TB-TServer.
+
+For example, to create a single-node cluster with pg_cron enabled using [yugabyted](../../../../reference/configuration/yugabyted/), use the following  command:
+
+```sh
+./bin/yugabyted start --master_flags "enable_pg_cron=true,allowed_preview_flags_csv=enable_pg_cron" --tserver_flags "enable_pg_cron=true,allowed_preview_flags_csv=enable_pg_cron" --ui false
+```
+
+By default, pg_cron runs on the `yugabyte` database. You can change this by setting the `ysql_cron_database_name` flag to your desired database name.
+
+After the flags are set, run the following command on the cron database with superuser privileges:
+
+```sql
+CREATE EXTENSION pg_cron;
+```
+
+For information on how to schedule jobs, refer to the [pg_cron](https://github.com/yugabyte/yugabyte-db/blob/master/src/postgres/third-party-extensions/pg_cron/README.md) documentation.