How can I measure the amount of space taken by blobs on a Firebird 2.1 database? - firebird

Question

I have a production database, using Firebird 2.1, where I need to find out how much space is used by each table, including the blobs. The blob-part is the tricky one, because it is not covered using the standard statistical report.
I do not have easy access to the server's desktop, so installing UDFs etc. is not a good solution.
How can I do this easily?

Answer 1

You can count total size of all BLOB fields in a database with following statement:
EXECUTE BLOCK RETURNS (BLOB_SIZE BIGINT)
AS
DECLARE VARIABLE RN CHAR(31) CHARACTER SET UNICODE_FSS;
DECLARE VARIABLE FN CHAR(31) CHARACTER SET UNICODE_FSS;
DECLARE VARIABLE S BIGINT;
BEGIN
BLOB_SIZE = 0;
FOR
SELECT r.rdb$relation_name, r.rdb$field_name
FROM rdb$relation_fields r JOIN rdb$fields f
ON r.rdb$field_source = f.rdb$field_name
WHERE f.rdb$field_type = 261
INTO :RN, :FN
DO BEGIN
EXECUTE STATEMENT
'SELECT SUM(OCTET_LENGTH(' || :FN || ')) FROM ' || :RN ||
' WHERE NOT ' || :FN || ' IS NULL'
INTO :S;
BLOB_SIZE = :BLOB_SIZE + COALESCE(:S, 0);
END
SUSPEND;
END

Answer 2

I modified the code example of Andrej to show the size of each blob field, not only the sum of all blobs.
And used SET TERM so you can copy&paste this snippet directly to tools like FlameRobin.
SET TERM #;
EXECUTE BLOCK
RETURNS (BLOB_SIZE BIGINT, TABLENAME CHAR(31), FIELDNAME CHAR(31) )
AS
DECLARE VARIABLE RN CHAR(31) CHARACTER SET UNICODE_FSS;
DECLARE VARIABLE FN CHAR(31) CHARACTER SET UNICODE_FSS;
DECLARE VARIABLE S BIGINT;
BEGIN
BLOB_SIZE = 0;
FOR
SELECT r.rdb$relation_name, r.rdb$field_name
FROM rdb$relation_fields r JOIN rdb$fields f
ON r.rdb$field_source = f.rdb$field_name
WHERE f.rdb$field_type = 261
INTO :RN, :FN
DO BEGIN
EXECUTE STATEMENT
'SELECT SUM(OCTET_LENGTH(' || :FN || ')) AS BLOB_SIZE, ''' || :RN || ''', ''' || :FN || '''
FROM ' || :RN ||
' WHERE NOT ' || :FN || ' IS NULL'
INTO :BLOB_SIZE, :TABLENAME, :FIELDNAME;
SUSPEND;
END
END
#
SET TERM ;#
This example doesn't work with ORDER BY, maybe a more elegant solution without EXECUTE BLOCK exists.