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Fix histogram memory management

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There are "local" histograms that are allocated by one thread for
one TABLE object, and "global" that are allocated for TABLE_SHARE.
This commit is contained in:
Sergei Petrunia
2021-08-29 23:55:39 +03:00
parent 032587e2dc
commit a93b377863
3 changed files with 50 additions and 11 deletions
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50
sql/sql_statistics.cc
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@@ -63,7 +63,8 @@
equal to "never".
*/
Histogram_base *create_histogram(MEM_ROOT *mem_root, Histogram_type hist_type);
Histogram_base *create_histogram(MEM_ROOT *mem_root, Histogram_type hist_type,
THD *owner);
/* Currently there are only 3 persistent statistical tables */
static const uint STATISTICS_TABLES= 3;
@@ -1222,15 +1223,16 @@ public:
char buff[MAX_FIELD_WIDTH];
String val(buff, sizeof(buff), &my_charset_bin);
uint fldno= COLUMN_STAT_HISTOGRAM;
Histogram_base *hist;
Field *stat_field= stat_table->field[fldno];
table_field->read_stats->set_not_null(fldno);
stat_field->val_str(&val);
hist= create_histogram(mem_root, table_field->read_stats->histogram_type_on_disk);
if (!hist)
Histogram_type hist_type=
table_field->read_stats->histogram_type_on_disk;
Histogram_base *hist;
if (!(hist= create_histogram(mem_root, hist_type, NULL)))
return NULL;
if (!hist->parse(mem_root, table_field,
table_field->read_stats->histogram_type_on_disk,
if (!hist->parse(mem_root, table_field, hist_type,
val.ptr(), val.length()))
{
table_field->read_stats->histogram_= hist;
@@ -2085,18 +2087,25 @@ public:
};
Histogram_base *create_histogram(MEM_ROOT *mem_root, Histogram_type hist_type)
Histogram_base *create_histogram(MEM_ROOT *mem_root, Histogram_type hist_type,
THD *owner)
{
Histogram_base *res= NULL;
switch (hist_type) {
case SINGLE_PREC_HB:
case DOUBLE_PREC_HB:
return new (mem_root) Histogram_binary();
res= new (mem_root) Histogram_binary();
break;
case JSON_HB:
return new (mem_root) Histogram_json();
res= new (mem_root) Histogram_json();
break;
default:
DBUG_ASSERT(0);
}
return NULL;
if (res)
res->set_owner(owner);
return res;
}
@@ -2691,6 +2700,25 @@ int alloc_statistics_for_table(THD* thd, TABLE *table)
DBUG_RETURN(0);
}
/*
Free the "local" statistics for table.
We only free the statistics that is not on MEM_ROOT and needs to be
explicitly freed.
*/
void free_statistics_for_table(THD *thd, TABLE *table)
{
for (Field **field_ptr= table->field; *field_ptr; field_ptr++)
{
// Only delete the histograms that are exclusivly owned by this thread
if ((*field_ptr)->collected_stats &&
(*field_ptr)->collected_stats->histogram_ &&
(*field_ptr)->collected_stats->histogram_->get_owner() == thd)
{
delete (*field_ptr)->collected_stats->histogram_;
(*field_ptr)->collected_stats->histogram_= NULL;
}
}
}
/**
@brief
@@ -2921,7 +2949,7 @@ void Column_statistics_collected::finish(MEM_ROOT *mem_root, ha_rows rows, doubl
if (hist_size != 0 && hist_type != INVALID_HISTOGRAM)
{
have_histogram= true;
histogram_= create_histogram(mem_root, hist_type);
histogram_= create_histogram(mem_root, hist_type, current_thd);
histogram_->init_for_collection(mem_root, hist_type, hist_size);
}