fix: uploader panic under db access error

[joeylichang]

Description

1. Polish uplader code
2. Add SQLDB params to config, include: ConnMaxLifetime, ConnMaxIdleTime, MaxIdleConns, MaxOpenConns
3. Add the params default values, if not set the config field will use the default value.

// SQLDB default configuration parmas
const (
	// DefaultConnMaxLifetime defines the default max liveness time of connection
	DefaultConnMaxLifetime = 3600
	// DefaultConnMaxIdleTime defines the default max idle time of connection
	DefaultConnMaxIdleTime = 60
	// DefaultMaxIdleConns defines the default max number of idle connections
	DefaultMaxIdleConns = 128
	// DefaultMaxOpenConns defines the default max number of open connections
	DefaultMaxOpenConns = 1024
)

Rationale

N/A

Example

N/A

Changes

Notable changes:
N/A

[sysvm]

LGTM