Join two df using the sqldf

I'm trying to join two tables using the same id of the species, but I'm not getting it.

Here are the steps below:

Importing the corrected file into TNRS for R

hp<-fread('tnrs_final.txt', header=T)

Now linking the tables using the unique ID of the species:

library(sqldf) #pacote 

juncao_dfs<-sqldf('select * from df_total left join hp on df_total.id_species=hp.user_id') #df_total é o outro df que quero juntar com hp.

The following message appears on the console:

  

Error: can not allocate vector of size 9.9 Mb

How do I get around this? Are there other packages or functions that do this?