Re: Recovering database after BBPcheckbats error

24 Aug 2022


      On 23/08/2022 16.59, imad hajj chahine wrote:
...
Hi Sjoerd,
The primary concern is being able to start the database, that's why I 
edited the BBP.dir.
Can you please elaborate on the solution ?
1. how to create the binary using shell and why the value 8.
The .tail1 (also .tail2 and .tail4) file indicates the BAT is for string 
values.  The .tail* file contains offsets into the corresponding .hteap 
file.  The number in the file name is the number of bytes used for each 
offset (a binary value).  Offset 8192+8 is the only offset that is 
guaranteed to point to a string (it's the very first string added).  The 
values in the .tail1 and .tail2 files are 8192 lower than the actual 
offset.  Hence the value 8.
...
2. as a dba how can I identify the tables touched by the missing BATs
    to rebuild the tables
You can look in the output of
select "schema","table","column",location from sys.storage();
The location column is the file name without extension.
...
I appreciate your time and help.
Many thanks.
On Tue, Aug 23, 2022 at 3:27 PM Sjoerd Mullender mailto:sjoerd@monetdb.org> wrote:
The new releases fixes the cause of the problem.  If you already have
    it, it doesn't magically disappear.
It BBPcheckbats complains about a too short *.tail1 file, you can
    create
    one, or extend the exising one, with bytes with the value 8 (binary
    value, not the ASCII digit) until the file is large enough.  Then you
    can start the database.  Note, there is loss of data.
The BBP.dir file contains the meta-data for the database, i.e. which
    BATs there are, what their types are, and how large they are.  Do not
    mess with it.
On 23/08/2022 13.41, imad hajj chahine wrote:
     > Hi,
     >
     > I am using version Jan2022-SP2, and after a server restart I had the
     > BBPcheckbats error.
     > I upgraded to the latest version Jan2022-SP4 as it has the fix
    for this
     > reported bug, and I am still unable to start the database.
     >
     > After manually editing the BBP.dir file and removing the entries on
     > which the database failed to load with messages similar to
    (BBPcheckbats
     >          file /bat/01/67/16774.tail1 too small (expected 143640,
    actual
     > 0), I managed to make the database start and connect to it and
    query the
     > tables successfully.
     >
     > Is this the right way to recover from this? what I am risking
    losing by
     > deleting these entries, should I have corrupted tables that are
    affected
     > by these entries?
     >
     > What is exactly the role of BBP.dir? any documentation describing
    the
     > use of this file.
     >
     > Appreciate your help.
     > Thank you.
     >
     >
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    Sjoerd Mullender
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