Dear Sawada-san, Thanks for giving comments!
> This behavior makes sense to me. But do we want to handle the case of > using environment variables too? Yeah, v5 does not consider which libpq parameters are specified by environment variables. Such a variable should be used when the dbname is not expressly written in the connection string. Such a path was added in the v6 patch. If the dbname is not determined after parsing the connection string, we call PQconndefaults() to get settings from environment variables and service files [1], then start to search dbname again. Below shows an example. ``` PGPORT=5431 PGUSER=kuroda PGDATABASE=postgres pg_basebackup -D data_N2 -R -v -> primary_conninfo = 'user=kuroda ... port=5431 ... dbname=postgres ... ' ``` > IIUC, > > pg_basebackup -D tmp -d "user=masahiko dbname=test_db" > > is equivalent to: > > PGDATABASE="user=masahiko dbname=test_db" pg_basebackup -D tmp The case won't work. I think You assumed that expanded_dbname like PQconnectdbParams() [2] can be used for enviroment variables, but it is not correct - it won't parse as connection string again. In the libpq layer, connection parameters are parsed in PQconnectStartParams()->conninfo_array_parse(). When expand_dbname is specified, the entry "dbname" is firstly checked and parsed its value. They are done at fe-connect.c:5846. The environment variables are checked and parsed in conninfo_add_defaults(), which is called from conninfo_array_parse(). However, it is done at fe-connect.c:5956 - the expand_dbname has already been done at that time. This means there is no chance that PGDATABASE is parsed as an expanded style. For example, if the pg_basebackup runs like below: PGDATABASE="user=kuroda dbname=postgres" pg_basebackup -D data_N2 -R -v The primary_conninfo written in the file will be: primary_conninfo = 'user=hayato ... dbname=''user=kuroda dbname=postgres''' [1]: https://www.postgresql.org/docs/devel/libpq-pgservice.html [2]: https://www.postgresql.org/docs/devel/libpq-connect.html#LIBPQ-PQCONNECTDBPARAMS Best Regards, Hayato Kuroda FUJITSU LIMITED https://www.fujitsu.com/
pg_basebackup-write-dbname.v0006.patch
Description: pg_basebackup-write-dbname.v0006.patch
