feat(config): make table name of pg backend configurable

config/config.md

@@ -296,6 +296,8 @@
 | `store_addrs` | Array | -- | Store server address default to etcd store.<br/>For postgres store, the format is:<br/>"password=password dbname=postgres user=postgres host=localhost port=5432"<br/>For etcd store, the format is:<br/>"127.0.0.1:2379" |
 | `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` |
+| `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_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. |
 | `enable_region_failover` | Bool | `false` | Whether to enable region failover.<br/>This feature is only available on GreptimeDB running on cluster mode and<br/>- Using Remote WAL<br/>- Using shared storage (e.g., s3). |

config/metasrv.example.toml

@@ -24,6 +24,14 @@ store_key_prefix = ""
 ## - `postgres_store`
 backend = "etcd_store"
 
+## Table name in RDS to store metadata. Effect when using a RDS kvbackend.
+## **Only used when backend is `postgres_store`.**
+meta_table_name = "greptime_metakv"
+
+## 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
+
 ## Datanode selector type.
 ## - `round_robin` (default value)
 ## - `lease_based`

src/meta-srv/src/bootstrap.rs

@@ -230,7 +230,7 @@ pub async fn metasrv_builder(
         (None, BackendImpl::PostgresStore) => {
             let pool = create_postgres_pool(opts).await?;
             // TODO(CookiePie): use table name from config.
-            let kv_backend = PgStore::with_pg_pool(pool, "greptime_metakv", opts.max_txn_ops)
+            let kv_backend = PgStore::with_pg_pool(pool, &opts.meta_table_name, opts.max_txn_ops)
                 .await
                 .context(error::KvBackendSnafu)?;
             // Client for election should be created separately since we need a different session keep-alive idle time.
@@ -240,6 +240,8 @@ pub async fn metasrv_builder(
                 election_client,
                 opts.store_key_prefix.clone(),
                 CANDIDATE_LEASE_SECS,
+                &opts.meta_table_name,
+                opts.meta_election_lock_id,
             )
             .await?;
             (kv_backend, Some(election))