Fix for lp:711565 "Index Condition Pushdown can make a thread hold MyISAM locks as well as be unKILLable for long time"

- In Maria/MyISAM: Release/re-acquire locks to give queries that wait on them a chance to make progress
- In Maria/MyISAM: Change from numeric constants to ICP_RES values.
- In Maria: Do check index condition in maria_rprev() (was lost in the merge/backport?)
- In Maria/MyISAM/XtraDB: Check if the query was killed, and return immediately if it was.

Added new storage engine error: HA_ERR_ABORTED_BY_USER, for handler to signal that it detected a kill of the query and aborted

Authors: Sergey Petrunia & Monty

include/my_base.h:
  Added HA_ERR_ABORTED_BY_USER, for handler to signal that it detected a kill of the query and aborted
include/my_handler.h:
  Added comment
mysql-test/r/myisam_icp.result:
  Updated test
mysql-test/t/myisam_icp.test:
  Drop used tables at start of test
  Added test case that can help with manual testing of killing index condition pushdown query.
mysys/my_handler_errors.h:
  Text for new storage engine error
sql/handler.cc:
  If engine got HA_ERR_ABORTED_BY_USER, send kill message.
sql/multi_range_read.cc:
  Return error code
storage/maria/ha_maria.cc:
  Added ma_killed_in_mariadb() to detect kill.
  Ensure that file->external_ref points to TABLE object.
storage/maria/ma_extra.c:
  Dummy test-if-killed for standalone
storage/maria/ma_key.c:
  If ma_check_index_cond() fails, set my_errno and info->cur_row.lastpos
storage/maria/ma_rkey.c:
  Release/re-acquire locks to give queries that wait on them a chance to make progress
  Check if the query was killed, and return immediately if it was
storage/maria/ma_rnext.c:
  Check if the query was killed, and return immediately if it was
  Added missing fast_ma_writeinfo(info)
storage/maria/ma_rnext_same.c:
  Check if the query was killed, and return immediately if it was
  Added missing fast_ma_writeinfo(info)
storage/maria/ma_rprev.c:
  Check if the query was killed, and return immediately if it was
  Added missing fast_ma_writeinfo(info) and ma_check_index_cond()
storage/maria/ma_search.c:
  Give error message if we find a wrong key
storage/maria/ma_static.c:
  Added pointer to test-if-killed function
storage/maria/maria_def.h:
  New prototypes
storage/myisam/ha_myisam.cc:
  Added mi_killed_in_mariadb()
  Ensure that file->external_ref points to TABLE object.
storage/myisam/mi_extra.c:
  Dummy test-if-killed for standalone
storage/myisam/mi_key.c:
  If ma_check_index_cond() fails, set my_errno and info->lastpos
storage/myisam/mi_rkey.c:
  Ensure that info->lastpos= HA_OFFSET_ERROR in case of error
  Release/re-acquire locks to give queries that wait on them a chance to make progress
  Check if the query was killed, and return immediately if it was
  Reorder code to do less things in case of error.
  Added missing fast_mi_writeinfo()
storage/myisam/mi_rnext.c:
  Check if the query was killed, and return immediately if it was
  Simplify old ICP code
  Added missing fast_ma_writeinfo(info)
storage/myisam/mi_rnext_same.c:
  Check if the query was killed, and return immediately if it was
  Added missing fast_mi_writeinfo(info)
storage/myisam/mi_rprev.c:
  Check if the query was killed, and return immediately if it was
  Simplify error handling of ICP
  Added missing fast_mi_writeinfo(info)
storage/myisam/mi_search.c:
  Give error message if we find a wrong key
storage/myisam/mi_static.c:
  Added pointer to test-if-killed function
storage/myisam/myisamdef.h:
  New prototypes
storage/xtradb/handler/ha_innodb.cc:
  Added DB_SEARCH_ABORTED_BY_USER and ha_innobase::is_thd_killed()
  Check if the query was killed, and return immediately if it was
storage/xtradb/handler/ha_innodb.h:
  Added prototype
storage/xtradb/include/db0err.h:
  Added DB_SEARCH_ABORTED_BY_USER
storage/xtradb/include/row0mysql.h:
  Added possible ICP errors
storage/xtradb/row/row0sel.c:
  Use ICP errors instead of constants.
  Detect if killed and return B_SEARCH_ABORTED_BY_USER

1 files changed, 18 insertions, 7 deletions

diff --git a/storage/maria/ma_rnext.c b/storage/maria/ma_rnext.c
index bdba5ff3a17..2fd8bf4e603 100644
--- a/storage/maria/ma_rnext.c
+++ b/storage/maria/ma_rnext.c
@@ -30,7 +30,7 @@ int maria_rnext(MARIA_HA *info, uchar *buf, int inx)
   uint flag;
   MARIA_SHARE *share= info->s;
   MARIA_KEYDEF *keyinfo;
-  int icp_res= 1;
+  ICP_RESULT icp_res= ICP_MATCH;
   DBUG_ENTER("maria_rnext");
 
   if ((inx = _ma_check_index(info,inx)) < 0)
@@ -92,8 +92,20 @@ int maria_rnext(MARIA_HA *info, uchar *buf, int inx)
   if (!error)
   {
     while (!(*share->row_is_visible)(info) ||
-           ((icp_res= ma_check_index_cond(info, inx, buf)) == 0))
+           ((icp_res= ma_check_index_cond(info, inx, buf)) == ICP_NO_MATCH))
     {
+      /*
+        If we are at the last key on the key page, allow writers to
+        access the index.
+      */
+      if (info->int_keypos >= info->int_maxpos &&
+          ma_yield_and_check_if_killed(info, inx))
+      {
+        /* my_errno is set by ma_yield_and_check_if_killed() */
+        error= 1;
+        break;
+      }
+
       /* Skip rows inserted by other threads since we got a lock */
       if  ((error= _ma_search_next(info, &info->last_key,
                                    SEARCH_BIGGER,
@@ -108,16 +120,15 @@ int maria_rnext(MARIA_HA *info, uchar *buf, int inx)
   info->update&= (HA_STATE_CHANGED | HA_STATE_ROW_CHANGED);
   info->update|= HA_STATE_NEXT_FOUND;
   
-  if (icp_res == 2)
-    my_errno=HA_ERR_END_OF_FILE; /* got beyond the end of scanned range */
-
-  if (error || icp_res != 1)
+  if (error || icp_res != ICP_MATCH)
   {
+    fast_ma_writeinfo(info);
     if (my_errno == HA_ERR_KEY_NOT_FOUND)
-      my_errno=HA_ERR_END_OF_FILE;
+      my_errno= HA_ERR_END_OF_FILE;
   }
   else if (!buf)
   {
+    fast_ma_writeinfo(info);
     DBUG_RETURN(info->cur_row.lastpos == HA_OFFSET_ERROR ? my_errno : 0);
   }
   else if (!(*info->read_record)(info, buf, info->cur_row.lastpos))