postgres parse_indent() function hang [closed]

Question

select parse_ident('abc,efi&xyz');

Will stay there for ever, not returning. But a similar command will finish.

select regexp_split_to_array('abc,efi&xyz', '[,&]');
 regexp_split_to_array 
-----------------------
 {abc,efi,xyz}
(1 row)

Not sure what's wrong with my database. I am running a vacuum full analyze at the moment. Not sure that cause the hang.

Answer 1

You're losing error messages,

# select parse_ident('abc,efi&xyz');
ERROR:  string is not a valid identifier: "abc,efi&xyz"

They also do different things:

• parse_ident takes a string a fully-qualified identifier -- something you can use to identify a thing in a database, and returns the breakdown of it in an array. For example, if you had a column named abc,efi&xyz on a table named table in a schema named schema in a database named db, you could do,

  SELECT parse_ident('"abc,efi&xyz".table.schema.db');
             parse_ident           
  ---------------------------------
   {"abc,efi&xyz",table,schema,db}
  (1 row)
  

  From this point you could use array addressing to identify the table, (parse_ident(...)[2]).

• regexp_split_to_array takes any string and simply splits it returning an array. Unlike parse_ident it doesn't require a fully-qualified identifier, and it doesn't understand ANSI-quotes inside the identifier (as I used in my example above).

Answer 2

I figured it out: I was running DbSchema program that is locking a lot of tables including the meta tables.

After terminating DbSchema, things started moving. I figured it out when I tried to 'drop table tmp;', and it also got hung. After terminating DbSchema, the drop table finished. Then the parse_ident() started to work. For some reason, DbSchema is locking the database even the meta data.

lbwf3=# select parse_ident('abc,efi&xyz');
ERROR:  string is not a valid identifier: "abc,efi&xyz"