Part 1:
As part of MCOL-3776 to address synchronization issue while accessing
the fTimeZone member of the Func class, mutex locks were added to the
accessor and mutator methods. However, this slows down processing
of TIMESTAMP columns in PrimProc significantly as all threads across
all concurrently running queries would serialize on the mutex. This
is because PrimProc only has a single global object for the functor
class (class derived from Func in utils/funcexp/functor.h) for a given
function name. To fix this problem:
(1) We remove the fTimeZone as a member of the Func derived classes
(hence removing the mutexes) and instead use the fOperationType
member of the FunctionColumn class to propagate the timezone values
down to the individual functor processing functions such as
FunctionColumn::getStrVal(), FunctionColumn::getIntVal(), etc.
(2) To achieve (1), a timezone member is added to the
execplan::CalpontSystemCatalog::ColType class.
Part 2:
Several functors in the Funcexp code call dataconvert::gmtSecToMySQLTime()
and dataconvert::mySQLTimeToGmtSec() functions for conversion between seconds
since unix epoch and broken-down representation. These functions in turn call
the C library function localtime_r() which currently has a known bug of holding
a global lock via a call to __tz_convert. This significantly reduces performance
in multi-threaded applications where multiple threads concurrently call
localtime_r(). More details on the bug:
https://sourceware.org/bugzilla/show_bug.cgi?id=16145
This bug in localtime_r() caused processing of the Functors in PrimProc to
slowdown significantly since a query execution causes Functors code to be
processed in a multi-threaded manner.
As a fix, we remove the calls to localtime_r() from gmtSecToMySQLTime()
and mySQLTimeToGmtSec() by performing the timezone-to-offset conversion
(done in dataconvert::timeZoneToOffset()) during the execution plan
creation in the plugin. Note that localtime_r() is only called when the
time_zone system variable is set to "SYSTEM".
This fix also required changing the timezone type from a std::string to
a long across the system.
data types TEXT, CHAR, VARCHAR, FLOAT and DOUBLE are not yet supported by vectorized path
This patch introduces an example for Google benchmarking suite to measure a perf diff
b/w legacy scan/filtering code and the templated version
This patch:
1. Removes the option to declare uncompressed columns (set columnstore_compression_type = 0).
2. Ignores [COMMENT '[compression=0] option at table or column level (no error messages, just disregard).
3. Removes the option to set more than 2 extents per file (ExtentsPreSegmentFile).
4. Updates rebuildEM tool to support up to 10 dictionary extent per dictionary segment file.
5. Adds check for `DBRootStorageType` for rebuildEM tool.
6. Renamed rebuildEM to mcsRebuildEM.
Logs for research purposes
Keep progress - may not build
Good interface to collect LBIDs and CPInfo's
Write Engine compiles with new interface
New interface breaks things the least way and allows for new features to be added gradually.
Still ironing design - rewriting parts of WE
Keep progress commit
Write Engine compiles, going to test
I could introduce crashes there. Let's see.
Disable logging for tests
Fixing build problems - keep progress commit
Changed related to new interface
Add back accidentally removed m_txnLBIDMap.find
Remove printf/cout; up-to-date comment for AddLBIDtoList
Add "auto" type annotation
Work on PR comments
Descriptive vector emptines check
MCOL-4409 This patch combines VDecimal and Decimal and makes
IDB_Decimal an alias for the result class
MCOL-4409 More boilerplate reduction in Func_mod
Removed couple TSInt128::toType() methods
Removed uint128 from joblist/lbidlist.*
Another toString() method for wide-decimal that is EMPTY/NULL aware
Unified decimal processing in WF functions
Fixed a potential issue in EqualCompData::operator() for
wide-decimal processing
Fixed some signedness warnings
WF::percentile runtime threw an exception b/c of wrong DT deduced from its argument
Replaced literals with constants
Tought WF_sum_avg::checkSumLimit to use refs instead of values
2. Set Decimal precision in SimpleColumn::evaluate().
3. Add support for int128_t in ConstantColumn.
4. Set IDB_Decimal::s128Value in buildDecimalColumn().
5. Use width 16 as first if predicate for branching based on decimal width.
There are multiple overloaded version of the low level DML write methods to
push down CSC column type. WE needs the type to convert values correctly.
Replaced WE_INT128 with CSC data type that is more informative.
Removed commented and obsolete code.
Replaced switch-case blocks with oneliners.
For some reason version buffer is not turned up for update queries which
means that the version number for dictionary blocks is not changed.
This can lead to dirty cache reads resulting in _CpNoTf_ in the results.
This patch turns on version buffer for updates.
This adds options which are user enabled to debug the LRU cache inside
ColumnStore. Specifically cache flushing.
It adds the following:
* PrimProc flush information when SIGUSR2 mode is enabled
* cpimport dictionary flush information when -d2 is used
* WriteEngineServer DML flush information to STDERR
