config+sqldb: make native SQL query config options configurable

diff --git a/config_test_native_sql.go b/config_test_native_sql.go
index 92e8353..8ee51d4 100644
--- a/config_test_native_sql.go
+++ b/config_test_native_sql.go
@@ -10,6 +10,7 @@ import (
 	"github.com/btcsuite/btcd/chaincfg/chainhash"
 	graphdb "github.com/lightningnetwork/lnd/graph/db"
 	"github.com/lightningnetwork/lnd/kvdb"
+	"github.com/lightningnetwork/lnd/lncfg"
 	"github.com/lightningnetwork/lnd/sqldb"
 	"github.com/lightningnetwork/lnd/sqldb/sqlc"
 )
@@ -30,10 +31,15 @@ func (d *DefaultDatabaseBuilder) getGraphStore(baseDB *sqldb.BaseDB,
 		},
 	)
 
+	queryConfig := d.cfg.DB.Sqlite.QueryConfig
+	if d.cfg.DB.Backend == lncfg.PostgresBackend {
+		queryConfig = d.cfg.DB.Postgres.QueryConfig
+	}
+
 	return graphdb.NewSQLStore(
 		&graphdb.SQLStoreConfig{
 			ChainHash: *d.cfg.ActiveNetParams.GenesisHash,
-			QueryCfg:  sqldb.DefaultQueryConfig(),
+			QueryCfg:  &queryConfig,
 		},
 		graphExecutor, opts...,
 	)
diff --git a/lncfg/db.go b/lncfg/db.go
index 3da1f4d..388d518 100644
--- a/lncfg/db.go
+++ b/lncfg/db.go
@@ -115,10 +115,18 @@ func DefaultDB() *DB {
 		},
 		Postgres: &sqldb.PostgresConfig{
 			MaxConnections: defaultPostgresMaxConnections,
+			QueryConfig: sqldb.QueryConfig{
+				MaxBatchSize: 250,
+				MaxPageSize:  10000,
+			},
 		},
 		Sqlite: &sqldb.SqliteConfig{
 			MaxConnections: defaultSqliteMaxConnections,
 			BusyTimeout:    defaultSqliteBusyTimeout,
+			QueryConfig: sqldb.QueryConfig{
+				MaxBatchSize: 250,
+				MaxPageSize:  10000,
+			},
 		},
 		UseNativeSQL:           false,
 		SkipNativeSQLMigration: false,
diff --git a/sample-lnd.conf b/sample-lnd.conf
index cba4021..22ffc39 100644
--- a/sample-lnd.conf
+++ b/sample-lnd.conf
@@ -1601,6 +1601,12 @@
 ; Whether to skip executing schema migrations.
 ; db.postgres.skipmigrations=false
 
+; The maximum number of elements to use in a native-SQL batch query IN clause.
+; db.postgres.query.max-batch-size=5000
+
+; The maximum number of records to fetch at a time in a paginated query during
+; native-SQL calls.
+; db.postgres.query.max-page-size=10500
 
 [sqlite]
 
@@ -1617,6 +1623,13 @@
 ; The maximum amount of time to wait to execute a query if the db is locked.
 ; db.sqlite.busytimeout=5s
 
+; The maximum number of elements to use in a native-SQL batch query IN clause.
+; db.sqlite.query.max-batch-size=250
+
+; The maximum number of records to fetch at a time in a paginated query during
+; native-SQL calls.
+; db.sqlite.query.max-page-size=100
+
 ; Raw pragma option pairs to be used when opening the sqlite db. The flag
 ; can be specified multiple times to set multiple options.
 ; Default:
diff --git a/sqldb/config.go b/sqldb/config.go
index 24e58b4..c5f49a9 100644
--- a/sqldb/config.go
+++ b/sqldb/config.go
@@ -28,6 +28,7 @@ type SqliteConfig struct {
 	MaxConnections int           `long:"maxconnections" description:"The maximum number of open connections to the database. Set to zero for unlimited."`
 	PragmaOptions  []string      `long:"pragmaoptions" description:"A list of pragma options to set on a database connection. For example, 'auto_vacuum=incremental'. Note that the flag must be specified multiple times if multiple options are to be set."`
 	SkipMigrations bool          `long:"skipmigrations" description:"Skip applying migrations on startup."`
+	QueryConfig    `group:"query" namespace:"query"`
 }
 
 // PostgresConfig holds the postgres database configuration.
@@ -38,6 +39,7 @@ type PostgresConfig struct {
 	Timeout        time.Duration `long:"timeout" description:"Database connection timeout. Set to zero to disable."`
 	MaxConnections int           `long:"maxconnections" description:"The maximum number of open connections to the database. Set to zero for unlimited."`
 	SkipMigrations bool          `long:"skipmigrations" description:"Skip applying migrations on startup."`
+	QueryConfig    `group:"query" namespace:"query"`
 }
 
 func (p *PostgresConfig) Validate() error {
diff --git a/sqldb/paginate.go b/sqldb/paginate.go
index 2a51218..d810325 100644
--- a/sqldb/paginate.go
+++ b/sqldb/paginate.go
@@ -6,20 +6,19 @@ import (
 )
 
 // QueryConfig holds configuration values for SQL queries.
+//
+//nolint:ll
 type QueryConfig struct {
 	// MaxBatchSize is the maximum number of items included in a batch
 	// query IN clauses list.
-	MaxBatchSize int
+	MaxBatchSize int `long:"max-batch-size" description:"The maximum number of items to include in a batch query IN clause. This is used for queries that fetch results based on a list of identifiers."`
 
 	// MaxPageSize is the maximum number of items returned in a single page
 	// of results. This is used for paginated queries.
-	MaxPageSize int32
+	MaxPageSize int32 `long:"max-page-size" description:"The maximum number of items to return in a single page of results. This is used for paginated queries."`
 }
 
 // DefaultQueryConfig returns a default configuration for SQL queries.
-//
-// TODO(elle): make configurable & have different defaults for SQLite and
-// Postgres.
 func DefaultQueryConfig() *QueryConfig {
 	return &QueryConfig{
 		MaxBatchSize: 250,