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Code Issues

Slightly better support for merge joins and IS NOT DISTINCT equalities.

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This commit is contained in:
dimitr 2010-01-12 11:08:45 +00:00
parent 431db6d6e4
commit 6eff77d30e
1 changed files with 16 additions and 25 deletions
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41
src/jrd/recsrc/MergeJoin.cpp
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@ -51,7 +51,10 @@ MergeJoin::MergeJoin(CompilerScratch* csb, size_t count,
for (size_t i = 0; i < count; i++)
{
fb_assert(args[i]);
m_args[i] = args[i];
fb_assert(keys[i] && keys[i]->nod_type == nod_sort);
m_keys[i] = keys[i];
}
}
@ -432,45 +435,33 @@ int MergeJoin::compare(thread_db* tdbb, jrd_nod* node1, jrd_nod* node2)
{
jrd_req* const request = tdbb->getRequest();
fb_assert(node1 && node1->nod_type == nod_sort);
fb_assert(node2 && node2->nod_type == nod_sort);
jrd_nod* const* ptr1 = node1->nod_arg;
jrd_nod* const* ptr2 = node2->nod_arg;
for (const jrd_nod* const* const end = ptr1 + node1->nod_count; ptr1 < end; ptr1++, ptr2++)
{
const dsc* const desc1 = EVL_expr(tdbb, *ptr1);
const ULONG flags = request->req_flags;
const bool null1 = (request->req_flags & req_null);
const dsc* const desc2 = EVL_expr(tdbb, *ptr2);
const bool null2 = (request->req_flags & req_null);
if (flags & req_null)
if (null1 && !null2)
{
if (!(request->req_flags & req_null))
{
return -1;
}
// AB: When both expression evaluated NULL then
// we return 0 ( (NULL = NULL) = true).
//
// Currently this (0 and higher) isn't used by the
// MERGE procedure, but when we allow MERGE to
// handle outer-joins we must not forget this one !!!
return 0;
return -1;
}
if (request->req_flags & req_null)
else if (null2 && !null1)
{
return 1;
}
// AB: MOV_compare can't handle NULL parameters
// therefore check before passing all null flags.
const int result = MOV_compare(desc1, desc2);
if (result != 0)
else if (!null1 && !null2)
{
return result;
const int result = MOV_compare(desc1, desc2);
if (result != 0)
{
return result;
}
}
}