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Earlier, when the database was queried we used to save
all the queried records in an ASCII format in the query file.
This caused issues like filename having ASCII delimiter and used
to take a lot of space. The tier.c file also had a lot of parsing code.
Here we changed the format of the query file to binary.
All the logic of serialization and formating of query record is done
by libgfdb. Libgfdb provides API,
gfdb_write_query_record() and gfdb_read_query_record(),
which the user i.e tier migrator and CTR xlator can use to
write to and read from query file.
With this binary format we save on disk space i.e reduce to 50% atleast
as we are saving GFID's in binary format 16 bytes and not the string format
which takes 36 bytes + We are not saving path of the file + we are also saving on
ASCII delimiters.
The on disk format of query record is as follows,
+---------------------------------------------------------------------------+
| Length of serialized query record | Serialized Query Record |
+---------------------------------------------------------------------------+
4 bytes Length of serialized query record
|
|
-------------------------------------------------|
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V
Serialized Query Record Format:
+---------------------------------------------------------------------------+
| GFID | Link count | <LINK INFO> |..... | FOOTER |
+---------------------------------------------------------------------------+
16 B 4 B Link Length 4 B
| |
| |
-----------------------------| |
| |
| |
V |
Each <Link Info> will be serialized as |
+-----------------------------------------------+ |
| PGID | BASE_NAME_LENGTH | BASE_NAME | |
+-----------------------------------------------+ |
16 B 4 B BASE_NAME_LENGTH |
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------------------------------------------------------------------------|
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V
FOOTER is a magic number 0xBAADF00D indicating the end of the record.
This also serves as a serialized schema validator.
Change-Id: I9db7416fd421e118dd44eafab8b535caafe50d5a
BUG: 1272207
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/12354
Reviewed-by: N Balachandran <nbalacha@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Dan Lambright <dlambrig@redhat.com>
Tested-by: Dan Lambright <dlambrig@redhat.com>
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