halfway through a query (as happens in "SET SESSION PROFILING = ...")
has a few side-effects, the worst of which is a memory leak for
prepared statements, which poke directly from the parser into the
profiling code (we don't have the query text when we need it) and
that overwrites a pointer to heap-allocated memory when the previous
statement turns on profiling.
Instead, now set a flag when we begin a new statement that tracks
whether profiling is on _at the start_ of the query. Use that to
track whether we gather info.
Additionally, use that AND use the state of the profiling variable
after the end of a query to know whether to store information about
the query that just finished.
B-g#24795: SHOW PROFILE implementation
Don't use memory roots to store profiling information, because
memory roots make freeing the data a no-op, and thus long-running
processes with profiling turned on the whole time could eventually
use all available memory.
Instead, use regular heap allocation and deallocation calls to
manage profiling data. Replace the leaky List usage with a similar-
behaving structure named "Queue".
Expand float size to avoid assert()ion failures.
"_db_func_" isn't a known linked object on some platforms, possibly
because it is occasionaly shadowed by DBUG variables. Avoid that
confusion.
to a single statement.
---
Bug#24795: SHOW PROFILE
Profiling is only partially functional on some architectures. Where
there is no getrusage() system call, presently Null values are
returned where it would be required. Notably, Windows needs some love
applied to make it as useful.
Syntax this adds:
SHOW PROFILES
SHOW PROFILE [types] [FOR QUERY n] [OFFSET n] [LIMIT n]
where "n" is an integer
and "types" is zero or many (comma-separated) of
"CPU"
"MEMORY" (not presently supported)
"BLOCK IO"
"CONTEXT SWITCHES"
"PAGE FAULTS"
"IPC"
"SWAPS"
"SOURCE"
"ALL"
It also adds a session variable (boolean) "profiling", set to "no"
by default, and (integer) profiling_history_size, set to 15 by
default.
This patch abstracts setting THDs' "proc_info" behind a macro that
can be used as a hook into the profiling code when profiling
support is compiled in. All future code in this line should use
that mechanism for setting thd->proc_info.
---
Tests are now set to omit the statistics.
---
Adds an Information_schema table, "profiling" for access to
"show profile" data.
---
Merge zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-5.0-community-3--bug24795
into zippy.cornsilk.net:/home/cmiller/work/mysql/mysql-5.0-community
---
Fix merge problems.
---
Fixed one bug in the query_source being NULL.
Updated test results.
---
Include more thorough profiling tests.
Improve support for prepared statements.
Use session-specific query IDs, starting at zero.
---
Selecting from I_S.profiling is no longer quashed in profiling, as
requested by Giuseppe.
Limit the size of captured query text.
No longer log queries that are zero length.
