Yup, This is a C hack, so I agree it should be done differently for
Drizzle.
my_close_table() is only used to close "tables" opened by
my_open_table().
In my_open_table() we have:
if (!(buffer = (char *) xt_malloc(self, size)))
return NULL;
table = (TABLE *) buffer;
buffer += sizeof(TABLE);
share = (TABLE_SHARE *) buffer;
So things have been setup so that:
share == (TABLE_SHARE *) ((char *) table + sizeof(TABLE))
To get rid of this hack, we need to look at the purpose of this code:
PBXT requires a reference (or a copy of) the internal MySQL/Drizzle
data dictionary (i.e. the structure that is created when a .frm
file is loaded).
This is required for 2 purposes:
1. To determine the internal MySQL row and key structures.
2. PBXT uses reference to MySQL collation sequence based comparison
routines.
MySQL/Drizzle supply this reference when opening a table handler.
However, for PBXT this is not good enough, because there are
background threads (like the recovery thread) that need the
information as well.
Ideally Drizzle would supply a set of callback services. One of
these would be to get a reference to Drizzle data dictionary for a
table, and another would be a function to release the reference.
Then I could remove the hack for the Drizzle case entirely.
On May 9, 2010, at 1:24 AM, Brian Aker wrote:
Hi!
This code:
static void my_close_table(TABLE *table)
{
#ifdef DRIZZLED
TABLE_SHARE *share;
share = (TABLE_SHARE *) ((char *) table + sizeof(TABLE));
share->free_table_share();
#else
delete_table(table, true); // TODO: Q, why did Stewart
remove this?
#endif
xt_free_ns(table);
}
This is not going to go well in Drizzle, since we the assumption
that the memory allocation will be aligned this way is wrong. In
my local tree I am going to drop the free_table_share().
I'm not really sure what to do though. I believe what you will be
wanting to do is call delete on table->s, though if what you are
using is an TableInstance then it should clean up just fine on its
own.
Is there something I can do to make this code a bit more
straightforward for you?
Cheers,
-Brian
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PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
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