library(shiny)
library(DBI)
library(pool)
pool <- dbPool(drv = RMySQL::MySQL(),dbname = "database",host = "localhost",username = "username",password = "password", port = 3306, unix.sock = "/var/run/mysqld/mysqld.sock")

ui <- fluidPage(
  uiOutput("names")
)

server <- function(input, output, session){
  getNames <- function(x){
    dbGetQuery(x, "SELECT DISTINCT names from dummyTable;")
  }

  refreshData <- reactive({
    invalidateLater(60000, session)
    getNames(pool)
  })
  output$names <- renderUI({
    selectInput(inputId = "name", label = "First names", choices = c(as.character(refreshData()[,1])))
  })
}

shinyApp(ui, server)