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*************************************************************************
Libgfdb |
*************************************************************************
Libgfdb provides abstract mechanism to record extra/rich metadata
required for data maintenance, such as data tiering/classification.
It provides consumer with API for recording and querying, keeping
the consumer abstracted from the data store used beneath for storing data.
It works in a plug-and-play model, where data stores can be plugged-in.
Presently we have plugin for Sqlite3. In the future will provide recording
and querying performance optimizer. In the current implementation the schema
of metadata is fixed.
Schema:
~~~~~~
GF_FILE_TB Table:
~~~~~~~~~~~~~~~~~
This table has one entry per file inode. It holds the metadata required to
make decisions in data maintenance.
GF_ID (Primary key) : File GFID (Universal Unique IDentifier in the namespace)
W_SEC, W_MSEC : Write wind time in sec & micro-sec
UW_SEC, UW_MSEC : Write un-wind time in sec & micro-sec
W_READ_SEC, W_READ_MSEC : Read wind time in sec & micro-sec
UW_READ_SEC, UW_READ_MSEC : Read un-wind time in sec & micro-sec
WRITE_FREQ_CNTR INTEGER : Write Frequency Counter
READ_FREQ_CNTR INTEGER : Read Frequency Counter
GF_FLINK_TABLE:
~~~~~~~~~~~~~~
This table has all the hardlinks to a file inode.
GF_ID : File GFID (Composite Primary Key)``|
GF_PID : Parent Directory GFID (Composite Primary Key) |-> Primary Key
FNAME : File Base Name (Composite Primary Key)__|
FPATH : File Full Path (Its redundant for now, this will go)
W_DEL_FLAG : This Flag is used for crash consistancy, when a link is unlinked.
i.e Set to 1 during unlink wind and during unwind this record
is deleted
LINK_UPDATE : This Flag is used when a link is changed i.e rename.
Set to 1 when rename wind and set to 0 in rename unwind
Libgfdb API:
~~~~~~~~~~~
Refer libglusterfs/src/gfdb/gfdb_data_store.h
Change-Id: I2e9fbab3878ce630a7f41221ef61017dc43db11f
BUG: 1194753
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Signed-off-by: Dan Lambright <dlambrig@redhat.com>
Signed-off-by: Joseph Fernandes <josferna@redhat.com>
Reviewed-on: http://review.gluster.org/9683
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
|
