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Fixed a performance problem: calls of the function imerge_list_and_tree

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could lead an to exponential growth of the imerge lists.
This commit is contained in:
Igor Babaev
2012-05-25 00:07:26 -07:00
parent a834af8c23
commit a948a323a0
1 changed files with 32 additions and 9 deletions
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37
sql/opt_range.cc
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@@ -1589,6 +1589,9 @@ int imerge_list_or_tree(RANGE_OPT_PARAM *param,
param Context info for the operation param Context info for the operation
merges IN/OUT List of imerges to push the range part of 'tree' into merges IN/OUT List of imerges to push the range part of 'tree' into
tree SEL_TREE whose range part is to be pushed into imerges tree SEL_TREE whose range part is to be pushed into imerges
replace if the pushdow operation for a imerge is a success
then the original imerge is replaced for the result
of the pushdown
DESCRIPTION DESCRIPTION
For each imerge from the list merges the function pushes the range part For each imerge from the list merges the function pushes the range part
@@ -1607,6 +1610,11 @@ int imerge_list_or_tree(RANGE_OPT_PARAM *param,
imerge with no trees then then not only nothing is added to the list imerge with no trees then then not only nothing is added to the list
merges but mi itself is removed from the list. merges but mi itself is removed from the list.
TODO
Optimize the code in order to not create new SEL_IMERGE and new SER_TREE
objects when 'replace' is TRUE. (Currently this function is called always
with this parameter equal to TRUE.)
RETURN RETURN
1 if no imerges are left in the list merges 1 if no imerges are left in the list merges
0 otherwise 0 otherwise
@@ -1615,7 +1623,8 @@ int imerge_list_or_tree(RANGE_OPT_PARAM *param,
static static
int imerge_list_and_tree(RANGE_OPT_PARAM *param, int imerge_list_and_tree(RANGE_OPT_PARAM *param,
List<SEL_IMERGE> *merges, List<SEL_IMERGE> *merges,
SEL_TREE *tree) SEL_TREE *tree,
bool replace)
{ {
SEL_IMERGE *imerge; SEL_IMERGE *imerge;
SEL_IMERGE *new_imerge= NULL; SEL_IMERGE *new_imerge= NULL;
@@ -1633,7 +1642,10 @@ int imerge_list_and_tree(RANGE_OPT_PARAM *param,
it.remove(); it.remove();
else else
{ {
new_merges.push_back(new_imerge); if (replace)
it.replace(new_imerge);
else
new_merges.push_back(new_imerge);
new_imerge= NULL; new_imerge= NULL;
} }
} }
@@ -7918,10 +7930,10 @@ int and_range_trees(RANGE_OPT_PARAM *param, SEL_TREE *tree1, SEL_TREE *tree2,
tree1 represents the formula RT1 AND MT1, tree1 represents the formula RT1 AND MT1,
where RT1 = R1_1 AND ... AND R1_k1, MT1=M1_1 AND ... AND M1_l1; where RT1 = R1_1 AND ... AND R1_k1, MT1=M1_1 AND ... AND M1_l1;
tree2 represents the formula RT2 AND MT2 tree2 represents the formula RT2 AND MT2
where RT2 = R2_1 AND ... AND R2_k2, MT2=M2_1 and ... and M2_l2. where RT2 = R2_1 AND ... AND R2_k2, MT2=M2_1 AND ... AND M2_l2.
The result tree will represent the formula of the the following structure: The result tree will represent the formula of the the following structure:
RT AND MT1 AND MT2 AND RT1MT2 AND RT2MT1, such that RT AND RT1MT2 AND RT2MT1, such that
rt is a tree obtained by range intersection of trees tree1 and tree2, rt is a tree obtained by range intersection of trees tree1 and tree2,
RT1MT2 = RT1M2_1 AND ... AND RT1M2_l2, RT1MT2 = RT1M2_1 AND ... AND RT1M2_l2,
RT2MT1 = RT2M1_1 AND ... AND RT2M1_l1, RT2MT1 = RT2M1_1 AND ... AND RT2M1_l1,
@@ -7939,11 +7951,22 @@ int and_range_trees(RANGE_OPT_PARAM *param, SEL_TREE *tree1, SEL_TREE *tree2,
tree, while the corresponding imerges are removed altogether from its tree, while the corresponding imerges are removed altogether from its
imerge part. imerge part.
NOTE. NOTE
The pushdown operation of range trees into imerges is needed to be able The pushdown operation of range trees into imerges is needed to be able
to construct valid imerges for the condition like this: to construct valid imerges for the condition like this:
key1_p1=c1 AND (key1_p2 BETWEEN c21 AND c22 OR key2 < c2) key1_p1=c1 AND (key1_p2 BETWEEN c21 AND c22 OR key2 < c2)
NOTE
Currently we do not support intersection between indexes and index merges.
When this will be supported the list of imerges for the result tree
should include also imerges from M1 and M2. That's why an extra parameter
is added to the function imerge_list_and_tree. If we call the function
with the last parameter equal to FALSE then MT1 and MT2 will be preserved
in the imerge list of the result tree. This can lead to the exponential
growth of the imerge list though.
Currently the last parameter of imerge_list_and_tree calls is always
TRUE.
RETURN RETURN
The result tree, if a success The result tree, if a success
0 - otherwise. 0 - otherwise.
@@ -7974,9 +7997,9 @@ SEL_TREE *tree_and(RANGE_OPT_PARAM *param, SEL_TREE *tree1, SEL_TREE *tree2)
} }
if (!tree1->merges.is_empty()) if (!tree1->merges.is_empty())
imerge_list_and_tree(param, &tree1->merges, tree2); imerge_list_and_tree(param, &tree1->merges, tree2, TRUE);
if (!tree2->merges.is_empty()) if (!tree2->merges.is_empty())
imerge_list_and_tree(param, &tree2->merges, tree1); imerge_list_and_tree(param, &tree2->merges, tree1, TRUE);
if (and_range_trees(param, tree1, tree2, tree1)) if (and_range_trees(param, tree1, tree2, tree1))
DBUG_RETURN(tree1); DBUG_RETURN(tree1);
imerge_list_and_list(&tree1->merges, &tree2->merges); imerge_list_and_list(&tree1->merges, &tree2->merges);