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MCOL-4957 Fix performance slowdown for processing TIMESTAMP columns.

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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.
This commit is contained in:
Gagan Goel
2022-02-09 19:03:00 -05:00
parent f67a37bcae
commit 973e5024d8
120 changed files with 1022 additions and 695 deletions
Download Patch File Download Diff File Expand all files Collapse all files

11
dbcon/mysql/ha_mcs_impl.h
View File

@ -29,9 +29,9 @@ extern int ha_mcs_impl_delete_table(const char* name);
extern int ha_mcs_impl_analyze(THD* thd, TABLE* table);
extern int ha_mcs_impl_open(const char* name, int mode, uint32_t test_if_locked);
extern int ha_mcs_impl_close(void);
extern int ha_mcs_impl_rnd_next(uchar* buf, TABLE* table);
extern int ha_mcs_impl_rnd_next(uchar* buf, TABLE* table, long timeZone);
extern int ha_mcs_impl_rnd_end(TABLE* table, bool is_derived_hand = false);
extern int ha_mcs_impl_write_row(const uchar* buf, TABLE* table, uint64_t rows_changed);
extern int ha_mcs_impl_write_row(const uchar* buf, TABLE* table, uint64_t rows_changed, long timeZone);
extern void ha_mcs_impl_start_bulk_insert(ha_rows rows, TABLE* table, bool is_cache_insert = false);
extern int ha_mcs_impl_end_bulk_insert(bool abort, TABLE* table);
extern int ha_mcs_impl_rename_table(const char* from, const char* to);
@ -45,9 +45,9 @@ extern int ha_mcs_impl_direct_update_delete_rows(bool execute, ha_rows* affected
extern int ha_mcs_impl_delete_row();
extern int ha_mcs_impl_rnd_pos(uchar* buf, uchar* pos);
extern int ha_mcs_impl_pushdown_init(mcs_handler_info* handler_info, TABLE* table);
extern int ha_mcs_impl_select_next(uchar* buf, TABLE* table);
extern int ha_mcs_impl_select_next(uchar* buf, TABLE* table, long timeZone);
extern int ha_mcs_impl_group_by_init(mcs_handler_info* handler_info, TABLE* table);
extern int ha_mcs_impl_group_by_next(TABLE* table);
extern int ha_mcs_impl_group_by_next(TABLE* table, long timeZone);
extern int ha_mcs_impl_group_by_end(TABLE* table);
#endif
@ -59,7 +59,8 @@ extern int ha_mcs_impl_group_by_end(TABLE* table);
extern int ha_mcs_impl_rename_table_(const char* from, const char* to, cal_impl_if::cal_connection_info& ci);
extern int ha_mcs_impl_write_row_(const uchar* buf, TABLE* table, cal_impl_if::cal_connection_info& ci,
ha_rows& rowsInserted);
extern int ha_mcs_impl_write_batch_row_(const uchar* buf, TABLE* table, cal_impl_if::cal_connection_info& ci);
extern int ha_mcs_impl_write_batch_row_(const uchar* buf, TABLE* table, cal_impl_if::cal_connection_info& ci,
long timeZone);
extern int ha_mcs_impl_write_last_batch(TABLE* table, cal_impl_if::cal_connection_info& ci, bool abort);
extern int ha_mcs_impl_commit_(handlerton* hton, THD* thd, bool all, cal_impl_if::cal_connection_info& ci);
extern int ha_mcs_impl_rollback_(handlerton* hton, THD* thd, bool all, cal_impl_if::cal_connection_info& ci);