Commented by: Simeon Bodurov (simeon.bodurov)

I have tried to connect with old Firebird 2.5 client to Firebird 3.0.4.32939 to test this issue. The same happens. When I connect with lc_ctype=WIN1251 parameter and execute SQL statement
SELECT 1 AS "АБВГДЕЖЗИЙКЛМНОП" FROM RDB$DATABASE
There is the same error:
arithmetic exception, numeric overflow, or string truncation.
string right truncation.

May be the problem is in the server, not in the client.

Commented by: @dyemanov

http://www.firebirdsql.org/file/documentation/release_notes/html/en/3_0/rnfb30-compat-sql.html#rnfb30-compat-psql-namelengths

Commented by: @dyemanov

16 cyrillic characters is 32 bytes which is beyond the limit for the identifier length (31 bytes).

Commented by: Simeon Bodurov (simeon.bodurov)

Dmitry,

Why 16 cyrillic characters are represented with 32 bytes when I am using encoding WIN1251 ???? How is done that ? And why there is so confusing error message "expected length 31, actual 16" ?
I can use up to 31 cyrillic characters as identifier when connection encoding is NONE, but when it is WIN1251 I cannot use more that 16 cyrillic characters ? I think that in WIN 1251 cyrillic characters are represented with 1byte. Not 2 bytes.
Every report that we made with Firebird 2.5 now have to be corrected to have identifiers with no more that 15 cyrillic characters or we have to use NONE as connection encoding, but that way we cannot modify stored procedures in database because cyrillic comments are not decoded properly ...