This patch introduces heuristics based flushing rate of dirty pages to
avoid IO bursts at checkpoint.
1) log_capacity / log_generated per second gives us number of seconds
in which ALL dirty pages need to be flushed. Based on this rough
assumption we can say that
n_dirty_pages / (log_capacity / log_generation_rate) = desired_flush_rate
2) We use weighted averages (hard coded to 20 seconds) of
log_generation_rate to avoid resonance.
3) From the desired_flush_rate we subtract the number of pages that have
been flushed due to LRU flushing. That gives us pages that we should
flush as part of flush_list cleanup. And that is the number (capped by
maximum io_capacity) that we try to flush from the master thread.
Knobs:
======
innodb_adaptive_flushing: boolean, global, dynamic, default TRUE.
Since this heuristic is very experimental and has the potential to
dramatically change the IO pattern I think it is a good idea to leave a
knob to turn it off.
Approved by: Heikki
Based on contribution from Google Inc.
This patch introduces a new parameter innodb_io_capacity to control the
rate at which master threads performs various tasks. The default value
is 200 and higher values imply more aggressive flushing and ibuf merges
from within the master thread.
This patch also changes the ibuf merge from synchronous to asynchronous.
Another minor change is not to force the master thread to wait for a
log flush to complete every second.
Approved by: Heikki
/*********************************
comments to Doxygen /** style like this:
/*****************************//**
This conversion was performed by the following command:
perl -i -e 'while(<ARGV>){if (m|^/\*{30}\**$|) {
s|\*{4}$|//**| if ++$com>1; $_ .= "\@file $ARGV\n" if $com==2}
print; if(eof){$.=0;undef $com}}' */*[ch] include/univ.i
This patch was created by running the following commands:
for i in */*[ch]; do doxygenify.pl $i; done
perl -i -pe 's#\*{3} \*/$#****/#' */*[ch]
where doxygenify.pl is
https://svn.innodb.com/svn/misc/trunk/tools/doxygenify.pl r510
Verified the consistency as follows:
(0) not too many /* in: */ or /* out: */ comments left in the code:
grep -l '/\*\s*\(in\|out\)[,:/]' */*[ch]
(1) no difference when ignoring blank lines, after stripping all
C90-style /* comments */, including multi-line ones, before and after
applying this patch:
perl -i -e 'undef $/;while(<ARGV>){s#/\*(.*?)\*/##gs;print}' */*[ch]
diff -I'^\s*$' --exclude .svn -ru TREE1 TREE2
(2) after stripping @return comments and !<, generated a diff and omitted
the hunks where /* out: */ function return comments were removed:
perl -i -e'undef $/;while(<ARGV>){s#!<##g;s#\n\@return\t.*?\*/# \*/#gs;print}'\
*/*[ch]
svn diff|
perl -e 'undef $/;$_=<>;s#\n-\s*/\* out[:,]([^\n]*?)(\n-[^\n]*?)*\*/##gs;print'
Some unintended changes were left. These will be removed in a
subsequent patch.
* Remove old Innobase copyright lines from C source files
* Add a reference to the GPLv2 license as recommended by the lawyers
at Oracle Legal
[Step 10/28]
ut_sprintf_timestamp_without_extra_chars(), ut_get_year_month_day(),
log_reset_first_header_and_checkpoint(): These functions are only used
in InnoDB Hot Backup.
This will help trim the dependencies of InnoDB Hot Backup.
recv_recovery_from_checkpoint_start(): Rename to
recv_recovery_from_checkpoint_start_func(), and remove the two first
parameters unless UNIV_LOG_ARCHIVE is defined. Define and use
the auxiliary macros TYPE_CHECKPOINT and LIMIT_LSN in the function.
struct recv_sys_struct: Remove archive_group unless UNIV_LOG_ARCHIVE
is defined.
Do not define LOG_ARCHIVE unless UNIV_LOG_ARCHIVE is defined.
in *.h files, so that the function signatures in the *.h and *.c files fully
match each other.
ut_dulint_sort(): Add a UNIV_INTERN qualifier also to the function definition.
log_block_calc_checksum(), log_block_get_checksum(): Add const qualifiers.
log_block_calc_checksum(): Split a long expression to more readable chunks.
Some compilers might optimize this better.
