1) Ensure "init_db.sql" and "test_db-sql" really get built.
2) Ensure the "*.def" files with NetWare linker options get distributed to the proper directories.
since this flag was explicitly removed in pushbuild for GCOV builds.
BUILD_CMD => ['sh', '-c', 'perl -i.bak -pe "s/ \\\\\$static_link//" ' .
'BUILD/compile-pentium-gcov; BUILD/compile-pentium-gcov'],
Moving $static_link to SETUP.sh broke this, and is now fixed.
Should this flag be needed on some platforms,
the proper location is compile-<platform>-gcov
Tested the amd64 and pentium64 build fine without it, and can run NDB tests.
1) We do not provide the "isam" table handler in 5.0 and up (different from "myisam" !),
so we do not need the ".def" files for the "isam"-specific tools.
2) Use "basename" to get the base name of a file, not a harder-to-read sed expression.
This is a performance bug, related to the parsing or 'OR' and 'AND' boolean
expressions.
Let N be the number of expressions involved in a OR (respectively AND).
When N=1
For example, "select 1" involve only 1 term: there is no OR operator.
In 4.0 and 4.1, parsing expressions not involving OR had no overhead.
In 5.0, parsing adds some overhead, with Select->expr_list.
With this patch, the overhead introduced in 5.0 has been removed,
so that performances for N=1 should be identical to the 4.0 performances,
which are optimal (there is no code executed at all)
The overhead in 5.0 was in fact affecting significantly some operations.
For example, loading 1 Million rows into a table with INSERTs,
for a table that has 100 columns, leads to parsing 100 Millions of
expressions, which means that the overhead related to Select->expr_list
is executed 100 Million times ...
Considering that N=1 is by far the most probable expression,
this case should be optimal.
When N=2
For example, "select a OR b" involves 2 terms in the OR operator.
In 4.0 and 4.1, parsing expressions involving 2 terms created 1 Item_cond_or
node, which is the expected result.
In 5.0, parsing these expression also produced 1 node, but with some extra
overhead related to Select->expr_list : creating 1 list in Select->expr_list
and another in Item_cond::list is inefficient.
With this patch, the overhead introduced in 5.0 has been removed
so that performances for N=2 should be identical to the 4.0 performances.
Note that the memory allocation uses the new (thd->mem_root) syntax
directly.
The cost of "is_cond_or" is estimated to be neglectable: the real problem
of the performance degradation comes from unneeded memory allocations.
When N>=3
For example, "select a OR b OR c ...", which involves 3 or more terms.
In 4.0 and 4.1, the parser had no significant cost overhead, but produced
an Item tree which is difficult to evaluate / optimize during runtime.
In 5.0, the parser produces a better Item tree, using the Item_cond
constructor that accepts a list of children directly, but at an extra cost
related to Select->expr_list.
With this patch, the code is implemented to take the best of the two
implementations:
- there is no overhead with Select->expr_list
- the Item tree generated is optimized and flattened.
This is achieved by adding children nodes into the Item tree directly,
with Item_cond::add(), which avoids the need for temporary lists and memory
allocation
Note that this patch also provide an extra optimization, that the previous
code in 5.0 did not provide: expressions are flattened in the Item tree,
based on what the expression already parsed is, and not based on the order
in which rules are reduced.
For example : "(a OR b) OR c", "a OR (b OR c)" would both be represented
with 2 Item_cond_or nodes before this patch, and with 1 node only with this
patch. The logic used is based on the mathematical properties of the OR
operator (it's associative), and produces a simpler tree.
Killing a SELECT query with KILL QUERY or KILL CONNECTION
causes a server crash if the query cache is enabled.
Normal evaluation of a query may be interrupted by the
KILL QUERY/CONNECTION statement, in this case the mysql_execute_command
function returns TRUE, and the thd->killed flag has true value.
In this case the result of the query may
be cached incompletely (omitting call to query_cache_insert inside
the net_real_write function), and next call to query_cache_end_of_result
may lead to server crash.
Thus, the query_cache_end_of_result function has been modified to abort
query cache in the case of killed thread.
Although the query cache doesn't support retrieval of statements containing
column level access control, it was still possible to cache such statements
thus wasting memory.
This patch extends the access control check on the target tables to avoid
caching a statement with column level restrictions.
Views are excepted and can be cached but only retrieved by super user account.
Use "SHOW TABLES FROM `db`" instead of $dbh->tables() in the
get_list_of_tables() routine.
The symptom is that, when used with recent versions of DBD::mysql,
mysqlhotcopy uses a double-qualified table name, for example:
Invalid db.table name 'test.test`.`x' at /usr/bin/mysqlhotcopy line 855.
This is caused by a change in DBD::mysql. See this diff:
http://svn.perl.org/viewcvs/modules/DBD-mysql/trunk/lib/DBD/mysql.pm?r1=9183&r2=9188
Basically, older DBD::mysql implemented a limited ->table_info method;
now the full method is implemented, and as a result DBI's ->tables()
method has access to the schema value, so it uses it.
