pg_dumpall: add page (#7646)

pages/common/pg_dumpall.md

@@ -0,0 +1,28 @@
+# pg_dumpall
+
+> Extract a PostgreSQL database cluster into a script file or other archive file.
+> More information: <https://www.postgresql.org/docs/current/app-pg-dumpall.html>.
+
+- Dump all databases:
+
+`pg_dumpall > {{path/to/file.sql}}`
+
+- Dump all databases using a specific username:
+
+`pg_dumpall --username={{username}} > {{path/to/file.sql}}`
+
+- Same as above, customize host and port:
+
+`pg_dumpall -h {{host}} -p {{port}} > {{output_file.sql}}`
+
+- Dump all databases into a custom-format archive file with moderate compression:
+
+`pg_dumpall -Fc > {{output_file.dump}}`
+
+- Dump only database data into an SQL-script file:
+
+`pg_dumpall --data-only > {{path/to/file.sql}}`
+
+- Dump only schema (data definitions) into an SQL-script file:
+
+`pg_dumpall -s > {{output_file.sql}}`