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MDEV-3798: EXPLAIN UPDATE/DELETE

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- Generate correct contents of `Extra` column for UPDATEs/DELETEs that use quick selects
- UPDATEs with used_key_is_modified=true will show "Using buffer"
This commit is contained in:
Sergey Petrunya
2013-10-09 09:40:33 +04:00
parent 69e6a2bb22
commit 161d687594
5 changed files with 73 additions and 20 deletions
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42
sql/sql_explain.cc
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@@ -793,6 +793,8 @@ int Explain_update::print_explain(Explain_query *query,
select_result_sink *output,
uint8 explain_flags)
{
StringBuffer<64> key_buf;
StringBuffer<64> key_len_buf;
StringBuffer<64> extra_str;
if (impossible_where || no_partitions)
{
@@ -807,8 +809,32 @@ int Explain_update::print_explain(Explain_query *query,
return res;
}
if (quick_info)
{
quick_info->print_key(&key_buf);
quick_info->print_key_len(&key_len_buf);
StringBuffer<64> quick_buf;
quick_info->print_extra(&quick_buf);
if (quick_buf.length())
{
extra_str.append(STRING_WITH_LEN("Using "));
extra_str.append(quick_buf);
}
}
else
{
key_buf.copy(key_str);
key_len_buf.copy(key_len_str);
}
if (using_where)
{
if (extra_str.length() !=0)
extra_str.append(STRING_WITH_LEN("; "));
extra_str.append(STRING_WITH_LEN("Using where"));
}
if (mrr_type.length() != 0)
{
@@ -816,7 +842,7 @@ int Explain_update::print_explain(Explain_query *query,
extra_str.append(STRING_WITH_LEN("; "));
extra_str.append(mrr_type);
}
if (using_filesort)
{
if (extra_str.length() !=0)
@@ -824,6 +850,13 @@ int Explain_update::print_explain(Explain_query *query,
extra_str.append(STRING_WITH_LEN("Using filesort"));
}
if (using_io_buffer)
{
if (extra_str.length() !=0)
extra_str.append(STRING_WITH_LEN("; "));
extra_str.append(STRING_WITH_LEN("Using buffer"));
}
/*
Single-table DELETE commands do not do "Using temporary".
"Using index condition" is also not possible (which is an unjustified limitation)
@@ -836,8 +869,8 @@ int Explain_update::print_explain(Explain_query *query,
used_partitions_set? used_partitions.c_ptr() : NULL,
jtype,
possible_keys_line.length()? possible_keys_line.c_ptr(): NULL,
key_str.length()? key_str.c_ptr() : NULL,
key_len_str.length() ? key_len_str.c_ptr() : NULL,
key_buf.length()? key_buf.c_ptr() : NULL,
key_len_buf.length() ? key_len_buf.c_ptr() : NULL,
NULL, /* 'ref' is always NULL in single-table EXPLAIN DELETE */
&rows,
extra_str.c_ptr());
@@ -846,7 +879,8 @@ int Explain_update::print_explain(Explain_query *query,
}
int Explain_insert::print_explain(Explain_query *query, select_result_sink *output,
int Explain_insert::print_explain(Explain_query *query,
select_result_sink *output,
uint8 explain_flags)
{
const char *select_type="INSERT";