tier/gfdb : Round-Robin read of query files

2016-02-14T14:23:17+00:00

1. Each brick on a host will get a separate query file.
2. While reading query record from these query files we
   read them in a Round-Robin manner.
3. When an error occurs during migration we rename it to
   query file with an time stamp and .err extension for
   better debugging.

Backport of http://review.gluster.org/13293

> Change-Id: I27c4285d24fd695d2d5cbd9fd7db3879d277ecc8
> BUG: 1302772
> Signed-off-by: Joseph Fernandes 
> Reviewed-on: http://review.gluster.org/13293
> Smoke: Gluster Build System 
> Tested-by: N Balachandran 
> NetBSD-regression: NetBSD Build System 
> Reviewed-by: Dan Lambright 
> CentOS-regression: Gluster Build System 

Change-Id: I9448f19c10a82fff9b1b3c9387c9026adc0742f1
BUG: 1306514
Signed-off-by: Joseph Fernandes 
Reviewed-on: http://review.gluster.org/13427
Smoke: Gluster Build System 
Reviewed-by: Joseph Fernandes
Tested-by: Joseph Fernandes
NetBSD-regression: NetBSD Build System 
CentOS-regression: Gluster Build System 
Reviewed-by: Dan Lambright

tier/libgfdb: Replacing ASCII query file with binary

2015-11-08T13:22:02+00:00

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
                                                      |
                                                      |
     -------------------------------------------------|
     |
     |
     V
   Serialized Query Record Format:
   +---------------------------------------------------------------------------+
   | GFID |  Link count   |    |.....                      | FOOTER |
   +---------------------------------------------------------------------------+
     16 B        4 B         Link Length                                  4 B
                                |                                          |
                                |                                          |
   -----------------------------|                                          |
   |                                                                       |
   |                                                                       |
   V                                                                       |
   Each  will be serialized as                                  |
   +-----------------------------------------------+                       |
   | PGID | BASE_NAME_LENGTH |      BASE_NAME      |                       |
   +-----------------------------------------------+                       |
     16 B       4 B             BASE_NAME_LENGTH                           |
                                                                           |
                                                                           |
   ------------------------------------------------------------------------|
   |
   |
   V
   FOOTER is a magic number 0xBAADF00D indicating the end of the record.
   This also serves as a serialized schema validator.

Backport of http://review.gluster.org/#/c/12354/

> Change-Id: I9db7416fd421e118dd44eafab8b535caafe50d5a
> BUG: 1272207
> Signed-off-by: Joseph Fernandes 
> Reviewed-on: http://review.gluster.org/12354
> Reviewed-by: N Balachandran 
> Tested-by: Gluster Build System 
> Reviewed-by: Dan Lambright 
> Tested-by: Dan Lambright 

Change-Id: I170c579027f2594a58706f826e3ddf89e34022f4
BUG: 1263619
Signed-off-by: Joseph Fernandes 
Reviewed-on: http://review.gluster.org/12535
Tested-by: NetBSD Build System 
Tested-by: Gluster Build System 
Reviewed-by: Dan Lambright 
Tested-by: Dan Lambright

glusterfs.git/libglusterfs/src/gfdb/gfdb_data_store_helper.c, branch v3.7.10

tier/gfdb : Round-Robin read of query files

tier/libgfdb: Replacing ASCII query file with binary