if cached query uses many tables
The problem was that query cache would not properly cache
queries which used 256 or more tables but yet would leave
behind query cache blocks pointing to freed (destroyed)
data. Later when invalidating (due to a truncate) query cache
would attempt to grab a lock which resided in the freed data,
leading to hangs or undefined behavior.
This was happening due to a improper return value from the
function responsible for registering the tables used in the
query (so the cache can be invalidated later if one of the
tables is modified). The function expected a return value of
type boolean (char, 8 bits) indicating success (1) or failure
(0) but the number of tables registered (unsigned int, 32 bits)
was being returned instead. This caused the function to return
failure for cases where it had actually succeed because when
a type (unsigned int) is converted to a narrower type (char),
the excess bits on the left are discarded. Thus if the 8
rightmost bits are zero, the return value will be 0 (failure).
The solution is to simply return true (1) only if the number of
registered table is greater than zero and false (0) otherwise.
WL#4165 Prepared statements: validation
WL#4166 Prepared statements: automatic re-prepare
Fixes
Bug#27430 Crash in subquery code when in PS and table DDL changed after PREPARE
Bug#27690 Re-execution of prepared statement after table was replaced with a view crashes
Bug#27420 A combination of PS and view operations cause error + assertion on shutdown
The basic idea of the patch is to keep track of table metadata between
prepared statement prepare and execute. If some table used in the statement
has changed, the prepared statement is re-prepared before execution.
See WL#4165 and WL#4166 contents and comments in the code for details
of the implementation.
Add pack_bits to pack_reclength for dynamic rows. This solves buffer a possible buffer overflow on update.
(This will probably solve bug #563)
Fix test for available file descriptors in mysqltest
Fixed core dump bug in replication tests when running without transactional table support
