write-after-read-protocol/sql/event_data_objects.cc at master · FlashSQL/write-after-read-protocol · GitHub

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This program is free software; you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

GNU General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program; if not, write to the Free Software

Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */

#include "event_data_objects.h"

#include "sql_parse.h" // parse_sql

#include "strfunc.h" // find_string_in_array

#include "sql_db.h" // get_default_db_collation

#include "sql_time.h" // interval_type_to_name,

// date_add_interval,

// calc_time_diff

#include "tztime.h" // my_tz_find, my_tz_OFFSET0, struct Time_zone

#include "auth_common.h" // EVENT_ACL, SUPER_ACL

#include "sp.h" // load_charset, load_collation

#include "events.h"

#include "event_db_repository.h"

#include "event_parse_data.h"

#include "sp_head.h"

#include "sql_show.h" // append_definer, append_identifier

#include "log.h"

#include "mysql/psi/mysql_sp.h"

/**

@addtogroup Event_Scheduler

#ifdef HAVE_PSI_INTERFACE

void init_scheduler_psi_keys()

{

const char *category= "scheduler";

PSI_server->register_statement(category, & Event_queue_element_for_exec::psi_info, 1);

}

PSI_statement_info Event_queue_element_for_exec::psi_info=

{ 0, "event", 0};

#endif

/*************************************************************************/

/**

Event_creation_ctx -- creation context of events.

class Event_creation_ctx :public Stored_program_creation_ctx,

public Sql_alloc

{

public:

static bool load_from_db(THD *thd,

MEM_ROOT *event_mem_root,

const char *db_name,

const char *event_name,

TABLE *event_tbl,

Stored_program_creation_ctx **ctx);

public:

virtual Stored_program_creation_ctx *clone(MEM_ROOT *mem_root)

{

return new (mem_root)

Event_creation_ctx(m_client_cs, m_connection_cl, m_db_cl);

}

protected:

virtual Object_creation_ctx *create_backup_ctx(THD *thd) const

{

We can avoid usual backup/restore employed in stored programs since we

know that this is a top level statement and the worker thread is

allocated exclusively to execute this event.

return NULL;

}

private:

Event_creation_ctx(const CHARSET_INFO *client_cs,

const CHARSET_INFO *connection_cl,

const CHARSET_INFO *db_cl)

: Stored_program_creation_ctx(client_cs, connection_cl, db_cl)

{ }

};

/**************************************************************************

Event_creation_ctx implementation.

**************************************************************************/

bool

Event_creation_ctx::load_from_db(THD *thd,

MEM_ROOT *event_mem_root,

const char *db_name,

const char *event_name,

TABLE *event_tbl,

Stored_program_creation_ctx **ctx)

{

/* Load character set/collation attributes. */

const CHARSET_INFO *client_cs;

const CHARSET_INFO *connection_cl;

const CHARSET_INFO *db_cl;

bool invalid_creation_ctx= FALSE;

if (load_charset(event_mem_root,

event_tbl->field[ET_FIELD_CHARACTER_SET_CLIENT],

thd->variables.character_set_client,

&client_cs))

{

sql_print_warning("Event '%s'.'%s': invalid value "

"in column mysql.event.character_set_client.",

db_name,

event_name);

invalid_creation_ctx= TRUE;

}

if (load_collation(event_mem_root,

event_tbl->field[ET_FIELD_COLLATION_CONNECTION],

thd->variables.collation_connection,

&connection_cl))

{

sql_print_warning("Event '%s'.'%s': invalid value "

"in column mysql.event.collation_connection.",

db_name,

event_name);

invalid_creation_ctx= TRUE;

}

if (load_collation(event_mem_root,

event_tbl->field[ET_FIELD_DB_COLLATION],

NULL,

&db_cl))

{

sql_print_warning("Event '%s'.'%s': invalid value "

"in column mysql.event.db_collation.",

db_name,

event_name);

invalid_creation_ctx= TRUE;

}

If we failed to resolve the database collation, load the default one

from the disk.

if (!db_cl)

db_cl= get_default_db_collation(thd, db_name);

/* Create the context. */

*ctx= new Event_creation_ctx(client_cs, connection_cl, db_cl);

return invalid_creation_ctx;

}

/*************************************************************************/

Initiliazes dbname and name of an Event_queue_element_for_exec

object

SYNOPSIS

Event_queue_element_for_exec::init()

RETURN VALUE

FALSE OK

TRUE Error (OOM)

bool

Event_queue_element_for_exec::init(LEX_STRING db, LEX_STRING n)

{

if (!(dbname.str= my_strndup(key_memory_Event_queue_element_for_exec_names,

db.str, dbname.length= db.length, MYF(MY_WME))))

return TRUE;

if (!(name.str= my_strndup(key_memory_Event_queue_element_for_exec_names,

n.str, name.length= n.length, MYF(MY_WME))))

{

my_free(dbname.str);

return TRUE;

}

return FALSE;

}

void Event_queue_element_for_exec::claim_memory_ownership()

{

my_claim(dbname.str);

my_claim(name.str);

}

Destructor

SYNOPSIS

Event_queue_element_for_exec::~Event_queue_element_for_exec()

{

my_free(dbname.str);

my_free(name.str);

}

Constructor

SYNOPSIS

Event_basic::Event_basic()

{

DBUG_ENTER("Event_basic::Event_basic");

/* init memory root */

init_sql_alloc(key_memory_event_basic_root, &mem_root, 256, 512);

dbname.str= name.str= NULL;

dbname.length= name.length= 0;

time_zone= NULL;

DBUG_VOID_RETURN;

}

Destructor

SYNOPSIS

Event_basic::Event_basic()

Event_basic::~Event_basic()

{

DBUG_ENTER("Event_basic::~Event_basic");

free_root(&mem_root, MYF(0));

DBUG_VOID_RETURN;

}

Short function to load a char column into a LEX_STRING

SYNOPSIS

Event_basic::load_string_field()

field_name The field( enum_events_table_field is not actually used

because it's unknown in event_data_objects.h)

fields The Field array

field_value The value

bool

Event_basic::load_string_fields(Field **fields, ...)

{

bool ret= FALSE;

va_list args;

enum enum_events_table_field field_name;

LEX_STRING *field_value;

DBUG_ENTER("Event_basic::load_string_fields");

va_start(args, fields);

field_name= (enum enum_events_table_field) va_arg(args, int);

while (field_name < ET_FIELD_COUNT)

{

field_value= va_arg(args, LEX_STRING *);

if ((field_value->str= get_field(&mem_root, fields[field_name])) == NullS)

{

ret= TRUE;

break;

}

field_value->length= strlen(field_value->str);

field_name= (enum enum_events_table_field) va_arg(args, int);

}

va_end(args);

DBUG_RETURN(ret);

}

bool

Event_basic::load_time_zone(THD *thd, const LEX_STRING tz_name)

{

String str(tz_name.str, &my_charset_latin1);

time_zone= my_tz_find(thd, &str);

return (time_zone == NULL);

}

Constructor

SYNOPSIS

Event_queue_element::Event_queue_element()

Event_queue_element::Event_queue_element():

on_completion(Event_parse_data::ON_COMPLETION_DROP),

status(Event_parse_data::ENABLED), expression(0), dropped(FALSE),

execution_count(0)

{

DBUG_ENTER("Event_queue_element::Event_queue_element");

starts= ends= execute_at= last_executed= 0;

starts_null= ends_null= execute_at_null= TRUE;

DBUG_VOID_RETURN;

}

Destructor

SYNOPSIS

Event_queue_element::Event_queue_element()

Event_queue_element::~Event_queue_element()

{

}

Constructor

SYNOPSIS

Event_timed::Event_timed()

Event_timed::Event_timed():

created(0), modified(0), sql_mode(0)

{

DBUG_ENTER("Event_timed::Event_timed");

init();

DBUG_VOID_RETURN;

}

Destructor

SYNOPSIS

Event_timed::~Event_timed()

{

}

Constructor

SYNOPSIS

Event_job_data::Event_job_data()

:sql_mode(0)

{

}

Init all member variables

SYNOPSIS

Event_timed::init()

void

Event_timed::init()

{

DBUG_ENTER("Event_timed::init");

definer_user= NULL_CSTR;

definer_host= NULL_CSTR;

body= NULL_STR;

comment= NULL_STR;

sql_mode= 0;

DBUG_VOID_RETURN;

}

/**

Load an event's body from a row from mysql.event.

@details This method is silent on errors and should behave like that.

Callers should handle throwing of error messages. The reason is that the

class should not know about how to deal with communication.

@return Operation status

@retval FALSE OK

@retval TRUE Error

bool

Event_job_data::load_from_row(THD *thd, TABLE *table)

{

char *ptr;

size_t len;

LEX_STRING tz_name;

DBUG_ENTER("Event_job_data::load_from_row");

if (!table)

DBUG_RETURN(TRUE);

if (table->s->fields < ET_FIELD_COUNT)

DBUG_RETURN(TRUE);

if (load_string_fields(table->field,

ET_FIELD_DB, &dbname,

ET_FIELD_NAME, &name,

ET_FIELD_BODY, &body,

ET_FIELD_DEFINER, &definer,

ET_FIELD_TIME_ZONE, &tz_name,

ET_FIELD_COUNT))

DBUG_RETURN(TRUE);

if (load_time_zone(thd, tz_name))

DBUG_RETURN(TRUE);

Event_creation_ctx::load_from_db(thd, &mem_root, dbname.str, name.str, table,

&creation_ctx);

ptr= strchr(definer.str, '@');

if (! ptr)

ptr= definer.str;

len= ptr - definer.str;

definer_user.str= strmake_root(&mem_root, definer.str, len);

definer_user.length= len;

len= definer.length - len - 1;

/* 1:because of @ */

definer_host.str= strmake_root(&mem_root, ptr + 1, len);

definer_host.length= len;

sql_mode= (sql_mode_t) table->field[ET_FIELD_SQL_MODE]->val_int();

DBUG_RETURN(FALSE);

}

/**

Load an event's body from a row from mysql.event.

@details This method is silent on errors and should behave like that.

Callers should handle throwing of error messages. The reason is that the

class should not know about how to deal with communication.

@return Operation status

@retval FALSE OK

@retval TRUE Error

bool

Event_queue_element::load_from_row(THD *thd, TABLE *table)

{

char *ptr;

MYSQL_TIME time;

LEX_STRING tz_name;

DBUG_ENTER("Event_queue_element::load_from_row");

if (!table)

DBUG_RETURN(TRUE);

if (table->s->fields < ET_FIELD_COUNT)

DBUG_RETURN(TRUE);

if (load_string_fields(table->field,

ET_FIELD_DB, &dbname,

ET_FIELD_NAME, &name,

ET_FIELD_DEFINER, &definer,

ET_FIELD_TIME_ZONE, &tz_name,

ET_FIELD_COUNT))

DBUG_RETURN(TRUE);

if (load_time_zone(thd, tz_name))

DBUG_RETURN(TRUE);

starts_null= table->field[ET_FIELD_STARTS]->is_null();

my_bool not_used= FALSE;

if (!starts_null)

{

table->field[ET_FIELD_STARTS]->get_date(&time, TIME_NO_ZERO_DATE);

starts= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);

}

ends_null= table->field[ET_FIELD_ENDS]->is_null();

if (!ends_null)

{

table->field[ET_FIELD_ENDS]->get_date(&time, TIME_NO_ZERO_DATE);

ends= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);

}

if (!table->field[ET_FIELD_INTERVAL_EXPR]->is_null())

expression= table->field[ET_FIELD_INTERVAL_EXPR]->val_int();

else

expression= 0;

If neigher STARTS and ENDS is set, then both fields are empty.

Hence, if ET_FIELD_EXECUTE_AT is empty there is an error.

execute_at_null= table->field[ET_FIELD_EXECUTE_AT]->is_null();

DBUG_ASSERT(!(starts_null && ends_null && !expression && execute_at_null));

if (!expression && !execute_at_null)

{

if (table->field[ET_FIELD_EXECUTE_AT]->get_date(&time,

TIME_NO_ZERO_DATE))

DBUG_RETURN(TRUE);

execute_at= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);

}

We load the interval type from disk as string and then map it to

an integer. This decouples the values of enum interval_type

and values actually stored on disk. Therefore the type can be

reordered without risking incompatibilities of data between versions.

if (!table->field[ET_FIELD_TRANSIENT_INTERVAL]->is_null())

{

int i;

char buff[MAX_FIELD_WIDTH];

String str(buff, sizeof(buff), &my_charset_bin);

LEX_STRING tmp;

table->field[ET_FIELD_TRANSIENT_INTERVAL]->val_str(&str);

if (!(tmp.length= str.length()))

DBUG_RETURN(TRUE);

tmp.str= str.c_ptr_safe();

i= find_string_in_array(interval_type_to_name, &tmp, system_charset_info);

if (i < 0)

DBUG_RETURN(TRUE);

interval= (interval_type) i;

}

if (!table->field[ET_FIELD_LAST_EXECUTED]->is_null())

{

table->field[ET_FIELD_LAST_EXECUTED]->get_date(&time,

TIME_NO_ZERO_DATE);

last_executed= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);

}

if ((ptr= get_field(&mem_root, table->field[ET_FIELD_STATUS])) == NullS)

DBUG_RETURN(TRUE);

DBUG_PRINT("load_from_row", ("Event [%s] is [%s]", name.str, ptr));

/* Set event status (ENABLED | SLAVESIDE_DISABLED | DISABLED) */

switch (ptr[0])

{

case 'E' :

status = Event_parse_data::ENABLED;

break;

case 'S' :

status = Event_parse_data::SLAVESIDE_DISABLED;

break;

case 'D' :

default:

status = Event_parse_data::DISABLED;

break;

}

if ((ptr= get_field(&mem_root, table->field[ET_FIELD_ORIGINATOR])) == NullS)

DBUG_RETURN(TRUE);

originator = table->field[ET_FIELD_ORIGINATOR]->val_int();

/* ToDo : Andrey . Find a way not to allocate ptr on event_mem_root */

if ((ptr= get_field(&mem_root,

table->field[ET_FIELD_ON_COMPLETION])) == NullS)

DBUG_RETURN(TRUE);

on_completion= (ptr[0]=='D'? Event_parse_data::ON_COMPLETION_DROP:

Event_parse_data::ON_COMPLETION_PRESERVE);

DBUG_RETURN(FALSE);

}

/**

Load an event's body from a row from mysql.event.

@details This method is silent on errors and should behave like that.

Callers should handle throwing of error messages. The reason is that the

class should not know about how to deal with communication.

@return Operation status

@retval FALSE OK

@retval TRUE Error

bool

Event_timed::load_from_row(THD *thd, TABLE *table)

{

char *ptr;

size_t len;

DBUG_ENTER("Event_timed::load_from_row");

if (Event_queue_element::load_from_row(thd, table))

DBUG_RETURN(TRUE);

if (load_string_fields(table->field,

ET_FIELD_BODY, &body,

ET_FIELD_BODY_UTF8, &body_utf8,

ET_FIELD_COUNT))

DBUG_RETURN(TRUE);

if (Event_creation_ctx::load_from_db(thd, &mem_root, dbname.str, name.str,

table, &creation_ctx))

{

push_warning_printf(thd,

Sql_condition::SL_WARNING,

ER_EVENT_INVALID_CREATION_CTX,

ER(ER_EVENT_INVALID_CREATION_CTX),

(const char *) dbname.str,

(const char *) name.str);

}

ptr= strchr(definer.str, '@');

if (! ptr)

ptr= definer.str;

len= ptr - definer.str;

definer_user.str= strmake_root(&mem_root, definer.str, len);

definer_user.length= len;

len= definer.length - len - 1;

/* 1:because of @ */

definer_host.str= strmake_root(&mem_root, ptr + 1, len);

definer_host.length= len;

created= table->field[ET_FIELD_CREATED]->val_int();

modified= table->field[ET_FIELD_MODIFIED]->val_int();

comment.str= get_field(&mem_root, table->field[ET_FIELD_COMMENT]);

if (comment.str != NullS)

comment.length= strlen(comment.str);

else

comment.length= 0;

sql_mode= (sql_mode_t) table->field[ET_FIELD_SQL_MODE]->val_int();

DBUG_RETURN(FALSE);

}

add_interval() adds a specified interval to time 'ltime' in time

zone 'time_zone', and returns the result converted to the number of

seconds since epoch (aka Unix time; in UTC time zone). Zero result

means an error.

static

my_time_t

add_interval(MYSQL_TIME *ltime, const Time_zone *time_zone,

interval_type scale, Interval interval)

{

if (date_add_interval(ltime, scale, interval))

return 0;

my_bool not_used;

return time_zone->TIME_to_gmt_sec(ltime, &not_used);

}

Computes the sum of a timestamp plus interval.

SYNOPSIS

get_next_time()

time_zone event time zone

next the sum

start add interval_value to this time

time_now current time

i_value quantity of time type interval to add

i_type type of interval to add (SECOND, MINUTE, HOUR, WEEK ...)

RETURN VALUE

0 OK

1 Error

NOTES

1) If the interval is conversible to SECOND, like MINUTE, HOUR, DAY, WEEK.

Then we use TIMEDIFF()'s implementation as underlying and number of

seconds as resolution for computation.

2) In all other cases - MONTH, QUARTER, YEAR we use MONTH as resolution

and PERIOD_DIFF()'s implementation

static

bool get_next_time(const Time_zone *time_zone, my_time_t *next,

my_time_t start, my_time_t time_now,

int i_value, interval_type i_type)

{

DBUG_ENTER("get_next_time");

DBUG_PRINT("enter", ("start: %lu now: %lu", (long) start, (long) time_now));

DBUG_ASSERT(start <= time_now);

longlong months=0, seconds=0;

switch (i_type) {

case INTERVAL_YEAR:

months= i_value*12;

break;

case INTERVAL_QUARTER:

/* Has already been converted to months */

case INTERVAL_YEAR_MONTH:

case INTERVAL_MONTH:

months= i_value;

break;

case INTERVAL_WEEK:

/* WEEK has already been converted to days */

case INTERVAL_DAY:

seconds= i_value*24*3600;

break;

case INTERVAL_DAY_HOUR:

case INTERVAL_HOUR:

seconds= i_value*3600;

break;

case INTERVAL_DAY_MINUTE:

case INTERVAL_HOUR_MINUTE:

case INTERVAL_MINUTE:

seconds= i_value*60;

break;

case INTERVAL_DAY_SECOND:

case INTERVAL_HOUR_SECOND:

case INTERVAL_MINUTE_SECOND:

case INTERVAL_SECOND:

seconds= i_value;

break;

case INTERVAL_DAY_MICROSECOND:

case INTERVAL_HOUR_MICROSECOND:

case INTERVAL_MINUTE_MICROSECOND:

case INTERVAL_SECOND_MICROSECOND:

case INTERVAL_MICROSECOND:

We should return an error here so SHOW EVENTS/ SELECT FROM I_S.EVENTS

would give an error then.

DBUG_RETURN(1);

break;

case INTERVAL_LAST:

DBUG_ASSERT(0);

}

DBUG_PRINT("info", ("seconds: %ld months: %ld", (long) seconds, (long) months));

MYSQL_TIME local_start;

MYSQL_TIME local_now;

/* Convert times from UTC to local. */

{

time_zone->gmt_sec_to_TIME(&local_start, start);

time_zone->gmt_sec_to_TIME(&local_now, time_now);

}

Interval interval;

memset(&interval, 0, sizeof(interval));

my_time_t next_time= 0;

if (seconds)

{

longlong seconds_diff;

long microsec_diff;

bool negative= calc_time_diff(&local_now, &local_start, 1,

&seconds_diff, &microsec_diff);

if (!negative)

{

The formula below returns the interval that, when added to

local_start, will always give the time in the future.

interval.second= seconds_diff - seconds_diff % seconds + seconds;

next_time= add_interval(&local_start, time_zone,

INTERVAL_SECOND, interval);

if (next_time == 0)

goto done;

}

if (next_time <= time_now)

{

If 'negative' is true above, then 'next_time == 0', and

'next_time <= time_now' is also true. If negative is false,

then next_time was set, but perhaps to the value that is less

then time_now. See below for elaboration.

DBUG_ASSERT(negative || next_time > 0);

If local_now < local_start, i.e. STARTS time is in the future

according to the local time (it always in the past according

to UTC---this is a prerequisite of this function), then

STARTS is almost always in the past according to the local

time too. However, in the time zone that has backward

Daylight Saving Time shift, the following may happen: suppose

we have a backward DST shift at certain date after 2:59:59,

i.e. local time goes 1:59:59, 2:00:00, ... , 2:59:59, (shift

here) 2:00:00 (again), ... , 2:59:59 (again), 3:00:00, ... .

Now suppose the time has passed the first 2:59:59, has been

shifted backward, and now is (the second) 2:20:00. The user

does CREATE EVENT with STARTS 'current-date 2:40:00'. Local

time 2:40:00 from create statement is treated by time

functions as the first such time, so according to UTC it comes

before the second 2:20:00. But according to local time it is

obviously in the future, so we end up in this branch.

Since we are in the second pass through 2:00:00--2:59:59, and

any local time form this interval is treated by system

functions as the time from the first pass, we have to find the

time for the next execution that is past the DST-affected

interval (past the second 2:59:59 for our example,

i.e. starting from 3:00:00). We do this in the loop until the

local time is mapped onto future UTC time. 'start' time is in

the past, so we may use 'do { } while' here, and add the first

interval right away.

Alternatively, it could be that local_now >= local_start. Now

for the example above imagine we do CREATE EVENT with STARTS

'current-date 2:10:00'. Local start 2:10 is in the past (now

is local 2:20), so we add an interval, and get next execution

time, say, 2:40. It is in the future according to local time,

but, again, since we are in the second pass through

2:00:00--2:59:59, 2:40 will be converted into UTC time in the

past. So we will end up in this branch again, and may add

intervals in a 'do { } while' loop.

Note that for any given event we may end up here only if event

next execution time will map to the time interval that is

passed twice, and only if the server was started during the

second pass, or the event is being created during the second

pass. After that, we never will get here (unless we again

start the server during the second pass). In other words,

such a condition is extremely rare.

interval.second= seconds;

{

next_time= add_interval(&local_start, time_zone,

INTERVAL_SECOND, interval);

if (next_time == 0)

goto done;

}

while (next_time <= time_now);

}

else

{

long diff_months= ((long) local_now.year - (long) local_start.year)*12 +

((long) local_now.month - (long) local_start.month);

Unlike for seconds above, the formula below returns the interval

that, when added to the local_start, will give the time in the

past, or somewhere in the current month. We are interested in

the latter case, to see if this time has already passed, or is

yet to come this month.

Note that the time is guaranteed to be in the past unless

(diff_months % months == 0), but no good optimization is

possible here, because (diff_months % months == 0) is what will

happen most of the time, as get_next_time() will be called right

after the execution of the event. We could pass last_executed

time to this function, and see if the execution has already

happened this month, but for that we will have to convert

last_executed from seconds since epoch to local broken-down

time, and this will greatly reduce the effect of the

optimization. So instead we keep the code simple and clean.

interval.month= (ulong) (diff_months - diff_months % months);

next_time= add_interval(&local_start, time_zone,

INTERVAL_MONTH, interval);

if (next_time == 0)

goto done;

if (next_time <= time_now)

{

interval.month= (ulong) months;

next_time= add_interval(&local_start, time_zone,

INTERVAL_MONTH, interval);

if (next_time == 0)

goto done;

}

DBUG_ASSERT(time_now < next_time);

*next= next_time;

done:

DBUG_PRINT("info", ("next_time: %ld", (long) next_time));

DBUG_RETURN(next_time == 0);

}

Computes next execution time.

SYNOPSIS

Event_queue_element::compute_next_execution_time()

RETURN VALUE

FALSE OK

TRUE Error

NOTES

The time is set in execute_at, if no more executions the latter is

set to 0.

bool

Event_queue_element::compute_next_execution_time()

{

my_time_t time_now;

DBUG_ENTER("Event_queue_element::compute_next_execution_time");

DBUG_PRINT("enter", ("starts: %lu ends: %lu last_executed: %lu this: 0x%lx",

(long) starts, (long) ends, (long) last_executed,

(long) this));

if (status != Event_parse_data::ENABLED)

{

DBUG_PRINT("compute_next_execution_time",

("Event %s is DISABLED", name.str));

goto ret;

}

/* If one-time, no need to do computation */

if (!expression)

{

/* Let's check whether it was executed */

if (last_executed)

{

DBUG_PRINT("info",("One-time event %s.%s of was already executed",

dbname.str, name.str));

dropped= (on_completion == Event_parse_data::ON_COMPLETION_DROP);

DBUG_PRINT("info",("One-time event will be dropped: %d.", dropped));

status= Event_parse_data::DISABLED;

}

goto ret;

}

time_now= (my_time_t) current_thd->query_start();

DBUG_PRINT("info",("NOW: [%lu]", (ulong) time_now));

/* if time_now is after ends don't execute anymore */

if (!ends_null && ends < time_now)

{

DBUG_PRINT("info", ("NOW after ENDS, don't execute anymore"));

/* time_now is after ends. don't execute anymore */

execute_at= 0;

execute_at_null= TRUE;

if (on_completion == Event_parse_data::ON_COMPLETION_DROP)

dropped= TRUE;

DBUG_PRINT("info", ("Dropped: %d", dropped));

status= Event_parse_data::DISABLED;

goto ret;

}

Here time_now is before or equals ends if the latter is set.

Let's check whether time_now is before starts.

If so schedule for starts.

if (!starts_null && time_now <= starts)

{

if (time_now == starts && starts == last_executed)

{

do nothing or we will schedule for second time execution at starts.

}

else

{

DBUG_PRINT("info", ("STARTS is future, NOW <= STARTS,sched for STARTS"));

starts is in the future

time_now before starts. Scheduling for starts

View remainder of file in raw view

write-after-read-protocol/sql/event_data_objects.cc at master · FlashSQL/write-after-read-protocol · GitHub

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