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MDEV-23221: A subquery causes crash

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* Fix the crash: IN-to-EXISTS rewrite causes an error (and so
  JOIN::optimize() fails with an error, too), don't call
  update_used_tables(). Terminate the query execution instead.

* Fix the cause of the error in the IN-to-EXISTS rewrite: don't do
  the rewrite if doing it will cause an error of this kind:
  This version of MariaDB doesn't yet support 'SUBQUERY in ROW in left
  expression of IN/ALL/ANY'

* Fix another issue exposed by this testcase:
  JOIN::setup_subquery_caches() may be invoked before any select has
  saved its query plan, and will crash because none of the SELECTs
  has called create_explain_query_if_not_exists() to create the Explain
  Data Structure for this SELECT.

TODO: When merging this to 10.2, remove the poorly-placed call to
create_explain_query_if_not_exists made by fix for M_D_E_V-16153
This commit is contained in:
Sergei Petrunia
2020-07-24 22:31:29 +03:00
parent 4b97f14a3d
commit b000d6952f
5 changed files with 139 additions and 4 deletions
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2
sql/sql_select.cc
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@ -1055,11 +1055,11 @@ int JOIN::optimize()
if (optimization_state != JOIN::NOT_OPTIMIZED)
return FALSE;
optimization_state= JOIN::OPTIMIZATION_IN_PROGRESS;
create_explain_query_if_not_exists(thd->lex, thd->mem_root);
int res= optimize_inner();
if (!res && have_query_plan != QEP_DELETED)
{
create_explain_query_if_not_exists(thd->lex, thd->mem_root);
have_query_plan= QEP_AVAILABLE;
save_explain_data(thd->lex->explain, false /* can overwrite */,
need_tmp,