feat: add optional schema for Postgres metadata tables (#6764)

* feat(meta): add optional schema for Postgres metadata tables

- Add `schema` option to specify a custom schema for metadata tables
- Update `PgStore` and `PgElection` to support optional schema
- Modify SQL templates to use schema when provided
- Add tests for schema support in Postgres backend

Signed-off-by: Logic <zqr10159@dromara.org>

* refactor(meta): remove unused `create_schema_statement` and simplify `PgSqlTemplateFactory`

- Remove `create_schema_statement` from `PgSqlTemplateSet` struct
- Simplify `PgSqlTemplateFactory` by removing `new` method and merging it with `with_schema`
- Update related tests to reflect these changes

Signed-off-by: Logic <zqr10159@dromara.org>

* refactor(meta-srv): remove unused imports

- Remove unused import of BoxedError from common_error::ext- Remove unused import of TlsOption from servers::tls

Signed-off-by: Logic <zqr10159@dromara.org>

* build(meta): update Postgres version and add error handling imports

- Update Postgres version to 17 in docker-compose.yml
- Add BoxedError import for error handling in meta-srv

Signed-off-by: Logic <zqr10159@dromara.org>

* feat(postgres): add support for optional schema in PgElection and related components

Signed-off-by: Logic <zqr10159@dromara.org>

* feat(postgres): add support for optional schema in PgElection and related components

Signed-off-by: Logic <zqr10159@dromara.org>

* fix(develop): update Postgres schema commands to specify host

Signed-off-by: Logic <zqr10159@dromara.org>

* refactor(postgres): simplify plugin options handling and update SQL examples

Signed-off-by: Logic <zqr10159@dromara.org>

* refactor(postgres): simplify plugin options handling and update SQL examples

Signed-off-by: Logic <zqr10159@dromara.org>

* fix(postgres): update meta_election_lock_id description for optional schema support

Signed-off-by: Logic <zqr10159@dromara.org>

* fix(postgres): add health check and fallback wait for Postgres in CI setup

* fix(postgres): update Docker setup for Postgres and add support for Postgres 15

* fix(postgres): remove redundant Postgres setup step in CI configuration

* Update tests-integration/fixtures/postgres/init.sql

Co-authored-by: Weny Xu <wenymedia@gmail.com>

* Update .github/workflows/develop.yml

* Update tests-integration/fixtures/docker-compose.yml

* Update src/common/meta/src/kv_backend/rds/postgres.rs

Co-authored-by: Weny Xu <wenymedia@gmail.com>

* Update src/common/meta/src/kv_backend/rds/postgres.rs

Co-authored-by: Weny Xu <wenymedia@gmail.com>

* Update src/common/meta/src/kv_backend/rds/postgres.rs

Co-authored-by: Weny Xu <wenymedia@gmail.com>

* Update src/common/meta/src/kv_backend/rds/postgres.rs

Co-authored-by: Weny Xu <wenymedia@gmail.com>

* fix: Refactor PostgreSQL backend to support optional schema in PgStore and related SQL templates

* feat: Update PostgreSQL configuration and add PG15 specific integration tests

* feat: Update PostgreSQL configuration and add PG15 specific integration tests

* refactor(postgres): update test schemas from 'greptime_schema' to 'test_schema'

* Update .github/workflows/develop.yml

* refactor: minor factor

Signed-off-by: WenyXu <wenymedia@gmail.com>

* chore: apply suggestions

Signed-off-by: WenyXu <wenymedia@gmail.com>

* fix: fix unit test

Signed-off-by: WenyXu <wenymedia@gmail.com>

---------

Signed-off-by: Logic <zqr10159@dromara.org>
Signed-off-by: WenyXu <wenymedia@gmail.com>
Co-authored-by: Weny Xu <wenymedia@gmail.com>

config/config.md

@@ -343,6 +343,7 @@
 | `store_key_prefix` | String | `""` | If it's not empty, the metasrv will store all data with this key prefix. |
 | `backend` | String | `etcd_store` | The datastore for meta server.<br/>Available values:<br/>- `etcd_store` (default value)<br/>- `memory_store`<br/>- `postgres_store`<br/>- `mysql_store` |
 | `meta_table_name` | String | `greptime_metakv` | Table name in RDS to store metadata. Effect when using a RDS kvbackend.<br/>**Only used when backend is `postgres_store`.** |
+| `meta_schema_name` | String | `greptime_schema` | Optional PostgreSQL schema for metadata table and election table name qualification.<br/>When PostgreSQL public schema is not writable (e.g., PostgreSQL 15+ with restricted public),<br/>set this to a writable schema. GreptimeDB will use `meta_schema_name`.`meta_table_name`.<br/>GreptimeDB will NOT create the schema automatically; please ensure it exists or the user has permission.<br/>**Only used when backend is `postgres_store`.** |
 | `meta_election_lock_id` | Integer | `1` | Advisory lock id in PostgreSQL for election. Effect when using PostgreSQL as kvbackend<br/>Only used when backend is `postgres_store`. |
 | `selector` | String | `round_robin` | Datanode selector type.<br/>- `round_robin` (default value)<br/>- `lease_based`<br/>- `load_based`<br/>For details, please see "https://docs.greptime.com/developer-guide/metasrv/selector". |
 | `use_memory_store` | Bool | `false` | Store data in memory. |

config/metasrv.example.toml

@@ -23,6 +23,14 @@ backend = "etcd_store"
 ## **Only used when backend is `postgres_store`.**
 meta_table_name = "greptime_metakv"
 
+## Optional PostgreSQL schema for metadata table and election table name qualification.
+## When PostgreSQL public schema is not writable (e.g., PostgreSQL 15+ with restricted public),
+## set this to a writable schema. GreptimeDB will use `meta_schema_name`.`meta_table_name`.
+## GreptimeDB will NOT create the schema automatically; please ensure it exists or the user has permission.
+## **Only used when backend is `postgres_store`.**
+
+meta_schema_name = "greptime_schema"
+
 ## Advisory lock id in PostgreSQL for election. Effect when using PostgreSQL as kvbackend
 ## Only used when backend is `postgres_store`.
 meta_election_lock_id = 1