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MCOL-4936 Disable binlog for DML statements.

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DML statements executed on the primary node in a ColumnStore
cluster do not need to be written to the primary's binlog. This
is due to ColumnStore's distributed storage architecture.

With this patch, we disable writing to binlog when a DML statement
(INSERT/DELETE/UPDATE/LDI/INSERT..SELECT) is performed on a ColumnStore
table. HANDLER::external_lock() calls are used to
  1. Turn OFF the OPTION_BIN_LOG flag
  2. Turn ON the OPTION_BIN_TMP_LOG_OFF flag
in THD::variables.option_bits during a WRITE lock call.

THD::variables.option_bits is restored back to the original state
during the UNLOCK call in HANDLER::external_lock().

Further, isDMLStatement() function is added to reduce code verbosity
to check if a given statement is a DML statement.

Note that with this patch, not writing to primary's binlog means
DML replication from a ColumnStore cluster to another ColumnStore
cluster or to another foreign engine will not work.
This commit is contained in:
Gagan Goel
2022-01-03 18:36:48 -05:00
parent edf404724c
commit 195425924d
4 changed files with 89 additions and 72 deletions
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28
dbcon/mysql/ha_mcs_sysvars.cpp
View File

@ -77,6 +77,18 @@ static MYSQL_THDVAR_ULONGLONG(
1
);
static MYSQL_THDVAR_ULONGLONG(
original_option_bits,
PLUGIN_VAR_NOSYSVAR | PLUGIN_VAR_NOCMDOPT,
"Storage for thd->variables.option_bits. For internal usage.",
NULL,
NULL,
0,
0,
~0U,
1
);
const char* mcs_select_handler_mode_values[] = {
"OFF",
"ON",
@ -377,6 +389,7 @@ st_mysql_sys_var* mcs_system_variables[] =
MYSQL_SYSVAR(compression_type),
MYSQL_SYSVAR(fe_conn_info_ptr),
MYSQL_SYSVAR(original_optimizer_flags),
MYSQL_SYSVAR(original_option_bits),
MYSQL_SYSVAR(select_handler),
MYSQL_SYSVAR(derived_handler),
MYSQL_SYSVAR(group_by_handler),
@ -443,6 +456,21 @@ void set_original_optimizer_flags(ulonglong ptr, THD* thd)
THDVAR(current_thd, original_optimizer_flags) = (uint64_t)(ptr);
}
ulonglong get_original_option_bits(THD* thd)
{
return (thd == NULL) ? 0 : THDVAR(thd, original_option_bits);
}
void set_original_option_bits(ulonglong value, THD* thd)
{
if (thd == NULL)
{
return;
}
THDVAR(thd, original_option_bits) = (uint64_t)(value);
}
mcs_select_handler_mode_t get_select_handler_mode(THD* thd)
{
return ( thd == NULL ) ? mcs_select_handler_mode_t::ON :