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[Maria-developers] Sprint 10.0: MDEV-8205 timediff returns null when comparing decimal time to time string value
by Alexander Barkov 16 Jun '15

16 Jun '15

Hi Sergei, I'm not sure what to do with this: > MariaDB [test]> select > -> timediff('2014-01-01 00:00:00' , '2014-01-01 01:00:00' ), > -> timediff(20140101000000.000 , 20140101010000.000 ), > -> timediff(20140101000000.000 , '2014-01-01 01:00:00' ), > -> datediff('2014-01-01 00:00:00' , '2014-01-02 01:00:00' ), > -> datediff(20140101000000.000 , 20140102010000.000 ), > -> datediff(20140101000000.000 , '2014-01-02 01:00:00' )\G > *************************** 1. row *************************** > timediff('2014-01-01 00:00:00' , '2014-01-01 01:00:00' ): -01:00:00 > timediff(20140101000000.000 , 20140101010000.000 ): -01:00:00.000 > timediff(20140101000000.000 , '2014-01-01 01:00:00' ): NULL > datediff('2014-01-01 00:00:00' , '2014-01-02 01:00:00' ): -1 > datediff(20140101000000.000 , 20140102010000.000 ): -1 > datediff(20140101000000.000 , '2014-01-02 01:00:00' ): -1 > 1 row in set (0.03 sec) Notice, it returns NULL in one case. The problem is in this piece of the code: > if (args[0]->get_time(&l_time1) || > args[1]->get_time(&l_time2) || > l_time1.time_type != l_time2.time_type) > return (null_value= 1); get_time() forces decimal-to-time conversion to truncate the date part and return MYSQL_TIMESTAMP_TIME. get_time() does not force string-to-time conversion to truncate the date part. It still returns the full MYSQL_TIMESTAMP_DATETIME. I'm afraid a lot of the code rely in this behavior. If we fix string-to-time conversion, mtr will start to fail in other cases. Any ideas what to do?

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[Maria-developers] MDEV-7502 Automatic provisioning of slave – retrieval of data from master
by Martin Kaluznik 16 Jun '15

16 Jun '15

Hello Kristian, after master-slave connection part, I proceeded to retrieval of data from master. There are two types of data which provisioning master will have to send, meta-data and row data. Meta-data For this I found only one method, pass output of SHOW CREATE * to slave in 'Query_log_event'. When I was looking for alternatives, I have found MySQL online backup work log where they are describing similar/same problem under High Level Architecture – Decision ( http://dev.mysql.com/worklog/task/?id=3574 ). Because of this, I find it unlikely, that there currently is better way. Because meta-data retrieval will take only small fraction of provisioning time, I think, that it could be implemented using 'Ed_connection' class, it executes query in string form and returns result set from within replication thread. Disadvantage of this solution is that query has to go through parser and all steps of generic execution, but on the other hand resulting code will be more independent from exact implementations, their pre-conditions and won’t contain any logical mistakes (locking, etc). Row data For this, same method with 'Ed_connection' could work, but it would be probably too big overhead – parser, result processing. So I created low level loop which goes through records of table and fills them in 'Write_rows_log_event'. Could you please check it, if it looks acceptable and I will then rewrite it to generic form, it is provisioning_send_info::send_table_data() function. https://github.com/f4rnham/server/blob/3d36cbfc20dff73d92ce61168dcc9805d68d… Right now it is working as expected on small test case. It goes through whole table at once and creates multiple row events when one would be enough. The same file also contains test of 'Ed_connection' and test of slave being able to receive and process 'Query_log_event'. Thanks for advice, Martin.

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[Maria-developers] Getting the columns from LEX or THD
by sriram patil 16 Jun '15

16 Jun '15

Hi all, I wanted to retrieve a tables columns i.e its schema definition when a query is executed. I figured out LEX and THD structures store these in different variables for different queries. I wanted to get the same when a simple INSERT query is executed, e.g INSERT INTO <table> VALUES(<values>). Where can I find it? Is there any mechanism to get a tables schema that will work for any kind of query? Thanks, Sriram

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Re: [Maria-developers] 8456b23: MDEV-5309 - RENAME TABLE does not check for existence of the table's engine
by Sergei Golubchik 16 Jun '15

16 Jun '15

Hi, Sergey! On Jun 15, svoj(a)mariadb.org wrote: > revision-id: 8456b231e9079be26c77da2a294ea1dac64d9d76 > parent(s): aad8667f8a4e2a26652494b29ee6c12824865ac8 > committer: Sergey Vojtovich > branch nick: mariadb > timestamp: 2015-06-15 15:49:00 +0400 > message: > > MDEV-5309 - RENAME TABLE does not check for existence of the table's engine > > When RENAME TABLE is executed, it apparently does not check whether the engine > is available (unlike ALTER TABLE .. RENAME, which does). It means that if the > engine in question was not loaded on some reason, the table might become > unusable, since the engine won't know about the change. > > With this patch RENAME TABLE fails if storage engine is not available. Ok to push. I'm not completely happy with the "table does not exist" error in this case, but I suspect that doing something reasonable might be not very easy. And it's a corner case anyway. Regards, Sergei

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[Maria-developers] unsubscribe
by Abdul Hakeem 14 Jun '15

14 Jun '15

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Re: [Maria-developers] 186e8e9: MDEV-5171: Add support for --innodb-optimize-keys to mysqldump.
by Sergei Golubchik 14 Jun '15

14 Jun '15

Hi, Jan! On May 04, Jan Lindström wrote: > revision-id: 186e8e91f3ce797258389f6d8729082f7d3ea164 > parent(s): aa5095627e2619bdad7916d33d1016802a84a9e1 > committer: Jan Lindström > branch nick: 10.0-git > timestamp: 2015-05-04 10:23:50 +0300 > message: > > MDEV-5171: Add support for --innodb-optimize-keys to mysqldump. > > Merged revision 93 from bzr+ssh://bazaar.launchpad.net/+branch/percona-server/5.6/ > authored by Alexey Kopytov. > > This patch expands the applicability of InnoDB fast index creation to > mysqldump, ALTER TABLE and OPTIMIZE TABLE as follows: > > 1. mysqldump has now a new option, --innodb-optimize-keys, which changes > the way InnoDB tables are dumped so that secondary and foreign keys are > created after loading the data thus taking advantage of fast index > creation. > > This part of the patch is an implementation of the feature request > reported as MySQL bug #49120. > > More specifically: > > - KEY, UNIQUE KEY and CONSTRAINT specifications are omitted from CREATE > TABLE corresponding to InnoDB tables. > > - an additional ALTER TABLE is issued after dumping the data to create > the previously omitted keys. > > Delaying foreign key creation does not introduce any additional risks as > mysqldump always prepends its output with SET FOREIGN_KEY_CHECKS=0 anyway. > > 2. When ALTER TABLE requires a table copy, secondary keys are now dropped > and recreated later after copying the data. The following restrictions > apply: > > - only non-unique keys can be involved in this optimization > > - if the table contains foreign keys, or a foreign key is being added as > a part of the current ALTER TABLE statement, the optimization is > disabled for all keys. > > This part of the patch is an implementation of the feature request > reported as MySQL bug #57583. > > 3. As OPTIMIZE TABLE is mapped to ALTER TABLE ... ENGINE=InnoDB for > InnoDB tables, it now also benefits from fast index creation with the > same restrictions as for ALTER TABLE. > diff --git a/client/client_priv.h b/client/client_priv.h > index 67a6e82..1846926 100644 > --- a/client/client_priv.h > +++ b/client/client_priv.h > @@ -94,6 +94,7 @@ enum options_client > OPT_SSL_CRL, OPT_SSL_CRLPATH, > OPT_USE_GTID, > OPT_GALERA_SST_MODE, > + OPT_INNODB_OPTIMIZE_KEYS, /* mysqldump */ Not needed, please, remove > OPT_MAX_CLIENT_OPTION /* should be always the last */ > }; > > diff --git a/client/mysqldump.c b/client/mysqldump.c > index e118198..0970082 100644 > --- a/client/mysqldump.c > +++ b/client/mysqldump.c > @@ -375,6 +386,11 @@ static struct my_option my_long_options[] = > "in dump produced with --dump-slave.", &opt_include_master_host_port, > &opt_include_master_host_port, 0, GET_BOOL, NO_ARG, > 0, 0, 0, 0, 0, 0}, > + {"innodb-optimize-keys", OPT_INNODB_OPTIMIZE_KEYS, Here use 0 instead of OPT_INNODB_OPTIMIZE_KEYS > + "Use InnoDB fast index creation by creating secondary indexes after " > + "dumping the data.", > + &opt_innodb_optimize_keys, &opt_innodb_optimize_keys, 0, GET_BOOL, NO_ARG, > + 0, 0, 0, 0, 0, 0}, > {"insert-ignore", OPT_INSERT_IGNORE, "Insert rows with INSERT IGNORE.", > &opt_ignore, &opt_ignore, 0, GET_BOOL, NO_ARG, 0, 0, 0, 0, > 0, 0}, > @@ -2581,6 +2597,359 @@ static inline my_bool general_log_or_slow_log_tables(const char *db, > } > > /* > + Find the first occurrence of a quoted identifier in a given string. Returns > + the pointer to the opening quote, and stores the pointer to the closing quote > + to the memory location pointed to by the 'end' argument, > + > + If no quoted identifiers are found, returns NULL (and the value pointed to by > + 'end' is undefined in this case). > +*/ > + > +static const char *parse_quoted_identifier(const char *str, > + const char **end) > +{ > + const char *from; > + const char *to; > + > + if (!(from= strchr(str, '`'))) > + return NULL; This is wrong, see below. Identifiers ar enot necessarily quoted, so this function should parse both quoted and not quoted identifiers (and renamed to, say, parse_next_identifier) > + > + to= from; > + > + while ((to= strchr(to + 1, '`'))) { > + /* > + Double backticks represent a backtick in identifier, rather than a quote > + character. > + */ > + if (to[1] == '`') > + { > + to++; > + continue; > + } > + > + break; > + } > + > + if (to <= from + 1) > + return NULL; /* Empty identifier */ > + > + *end= to; > + > + return from; > +} > + > +/* > + Parse the specified key definition string and check if the key contains an > + AUTO_INCREMENT column as the first key part. We only check for the first key > + part, because unlike MyISAM, InnoDB does not allow the AUTO_INCREMENT column > + as a secondary key column, i.e. the AUTO_INCREMENT column would not be > + considered indexed for such key specification. > +*/ > +static my_bool contains_autoinc_column(const char *autoinc_column, > + const char *keydef, > + key_type_t type) > +{ > + const char *from, *to; > + uint idnum; > + > + DBUG_ASSERT(type != KEY_TYPE_NONE); > + > + if (autoinc_column == NULL) > + return FALSE; > + > + idnum= 0; > + > + /* > + There is only 1 iteration of the following loop for type == KEY_TYPE_PRIMARY > + and 2 iterations for type == KEY_TYPE_UNIQUE / KEY_TYPE_NON_UNIQUE. > + */ > + while ((from= parse_quoted_identifier(keydef, &to))) > + { > + idnum++; > + > + /* > + Skip the check if it's the first identifier and we are processing a > + secondary key. > + */ > + if ((type == KEY_TYPE_PRIMARY || idnum != 1) && > + !strncmp(autoinc_column, from + 1, to - from - 1)) > + return TRUE; > + > + /* > + Check only the first (for PRIMARY KEY) or the second (for secondary keys) > + quoted identifier. > + */ > + if ((idnum == 1 + MY_TEST(type != KEY_TYPE_PRIMARY))) > + break; > + > + keydef= to + 1; > + } > + > + return FALSE; > +} > + > +/* > + Find a node in the skipped keys list whose name matches a quoted > + identifier specified as 'id_from' and 'id_to' arguments. > +*/ > + > +static LIST *find_matching_skipped_key(const char *id_from, > + const char *id_to) > +{ > + LIST *list; > + size_t id_len; > + > + id_len= id_to - id_from + 1; > + DBUG_ASSERT(id_len > 2); > + > + for (list= skipped_keys_list; list; list= list_rest(list)) > + { > + const char *keydef; > + const char *keyname_from; > + const char *keyname_to; > + size_t keyname_len; > + > + keydef= list->data; > + > + if ((keyname_from= parse_quoted_identifier(keydef, &keyname_to))) > + { > + keyname_len= keyname_to - keyname_from + 1; > + > + if (id_len == keyname_len && > + !strncmp(keyname_from, id_from, id_len)) > + return list; > + } > + } > + > + return NULL; > +} > + > +/* > + Remove secondary/foreign key definitions from a given SHOW CREATE TABLE string > + and store them into a temporary list to be used later. > + > + SYNOPSIS > + skip_secondary_keys() > + create_str SHOW CREATE TABLE output > + has_pk TRUE, if the table has PRIMARY KEY > + (or UNIQUE key on non-nullable columns) > + > + > + DESCRIPTION > + > + Stores all lines starting with "KEY" or "UNIQUE KEY" > + into skipped_keys_list and removes them from the input string. > + Ignoring FOREIGN KEYS constraints when creating the table is ok, because > + mysqldump sets foreign_key_checks to 0 anyway. > +*/ > + > +static void skip_secondary_keys(char *create_str, my_bool has_pk) > +{ > + char *ptr, *strend; > + char *last_comma= NULL; > + my_bool pk_processed= FALSE; > + char *autoinc_column= NULL; > + my_bool has_autoinc= FALSE; > + key_type_t type; > + const char *constr_from; > + const char *constr_to; > + LIST *keydef_node; > + my_bool keys_processed= FALSE; > + > + strend= create_str + strlen(create_str); > + > + ptr= create_str; > + while (*ptr && !keys_processed) > + { please, fix the coding style (here and everywhere in the patch) to follow the rest of the file. That is while { char *tmp, *orig_ptr, c; ... > + char *tmp, *orig_ptr, c; > + > + orig_ptr= ptr; > + /* Skip leading whitespace */ > + while (*ptr && my_isspace(charset_info, *ptr)) > + ptr++; > + > + /* Read the next line */ > + for (tmp= ptr; *tmp != '\n' && *tmp != '\0'; tmp++); > + > + c= *tmp; > + *tmp= '\0'; /* so strstr() only processes the current line */ > + > + if (!strncmp(ptr, "CONSTRAINT ", sizeof("CONSTRAINT ") - 1) && > + (constr_from= parse_quoted_identifier(ptr, &constr_to)) && yuck! identifiers do not have to be quoted. this code needs to be fixed to accept non-quoted identifiers too. > + (keydef_node= find_matching_skipped_key(constr_from, constr_to))) > + { > + char *keydef; > + size_t keydef_len; > + > + /* > + There's a skipped key with the same name as the constraint name. Let's > + put it back before the current constraint definition and remove from the > + skipped keys list. 1. fix the formatting, please 2. why not to create the FK constraint afterwards? > + */ > + keydef= keydef_node->data; > + keydef_len= strlen(keydef) + 5; /* ", \n " */ > + > + memmove(orig_ptr + keydef_len, orig_ptr, strend - orig_ptr + 1); > + memcpy(ptr, keydef, keydef_len - 5); > + memcpy(ptr + keydef_len - 5, ", \n ", 5); > + > + skipped_keys_list= list_delete(skipped_keys_list, keydef_node); > + my_free(keydef); > + my_free(keydef_node); > + > + strend+= keydef_len; > + orig_ptr+= keydef_len; > + ptr+= keydef_len; > + tmp+= keydef_len; > + > + type= KEY_TYPE_NONE; > + } > + else if (!strncmp(ptr, "UNIQUE KEY ", sizeof("UNIQUE KEY ") - 1)) > + type= KEY_TYPE_UNIQUE; > + else if (!strncmp(ptr, "KEY ", sizeof("KEY ") - 1)) > + type= KEY_TYPE_NON_UNIQUE; > + else if (!strncmp(ptr, "PRIMARY KEY ", sizeof("PRIMARY KEY ") - 1)) > + type= KEY_TYPE_PRIMARY; > + else > + type= KEY_TYPE_NONE; > + > + has_autoinc= (type != KEY_TYPE_NONE) ? > + contains_autoinc_column(autoinc_column, ptr, type) : FALSE; > + > + /* Is it a secondary index definition? */ > + if (c == '\n' && > + ((type == KEY_TYPE_UNIQUE && (pk_processed || !has_pk)) || > + type == KEY_TYPE_NON_UNIQUE) && !has_autoinc) > + { > + char *data, *end= tmp - 1; > + > + /* Remove the trailing comma */ > + if (*end == ',') > + end--; > + data= my_strndup(ptr, end - ptr + 1, MYF(MY_FAE)); > + skipped_keys_list= list_cons(data, skipped_keys_list); > + > + memmove(orig_ptr, tmp + 1, strend - tmp); > + ptr= orig_ptr; > + strend-= tmp + 1 - ptr; > + > + /* Remove the comma on the previos line */ > + if (last_comma != NULL) > + { > + *last_comma= ' '; > + } > + } > + else > + { > + char *end; > + > + if (last_comma != NULL && *ptr == ')') > + { > + keys_processed= TRUE; > + } > + else if (last_comma != NULL && !keys_processed) > + { > + /* > + It's not the last line of CREATE TABLE, so we have skipped a key > + definition. We have to restore the last removed comma. > + */ > + *last_comma= ','; > + } > + > + /* > + If we are skipping a key which indexes an AUTO_INCREMENT column, it is > + safe to optimize all subsequent keys, i.e. we should not be checking for > + that column anymore. > + */ > + if (type != KEY_TYPE_NONE && has_autoinc) > + { > + DBUG_ASSERT(autoinc_column != NULL); > + > + my_free(autoinc_column); > + autoinc_column= NULL; > + } > + > + if ((has_pk && type == KEY_TYPE_UNIQUE && !pk_processed) || > + type == KEY_TYPE_PRIMARY) > + pk_processed= TRUE; > + > + if (strstr(ptr, "AUTO_INCREMENT") && *ptr == '`') > + { > + /* > + The first secondary key defined on this column later cannot be > + skipped, as CREATE TABLE would fail on import. Unless there is a > + PRIMARY KEY and it indexes that column. > + */ > + for (end= ptr + 1; > + /* Skip double backticks as they are a part of identifier */ > + *end != '\0' && (*end != '`' || end[1] == '`'); > + end++) > + /* empty */; > + > + if (*end == '`' && end > ptr + 1) > + { > + DBUG_ASSERT(autoinc_column == NULL); > + > + autoinc_column= my_strndup(ptr + 1, end - ptr - 1, MYF(MY_FAE)); Eh? Why does it need to strdup? > + } > + } > + > + *tmp= c; > + > + if (tmp[-1] == ',') > + last_comma= tmp - 1; > + ptr= (*tmp == '\0') ? tmp : tmp + 1; > + } > + } > + > + my_free(autoinc_column); > +} > + > +/* > + Check if the table has a primary key defined either explicitly or > + implicitly (i.e. a unique key on non-nullable columns). > + > + SYNOPSIS > + my_bool has_primary_key(const char *table_name) > + > + table_name quoted table name > + > + RETURNS TRUE if the table has a primary key > + > + DESCRIPTION > +*/ > + > +static my_bool has_primary_key(const char *table_name) > +{ > + MYSQL_RES *res= NULL; > + MYSQL_ROW row; > + char query_buff[QUERY_LENGTH]; > + my_bool has_pk= TRUE; > + > + my_snprintf(query_buff, sizeof(query_buff), > + "SELECT COUNT(*) FROM INFORMATION_SCHEMA.COLUMNS WHERE " > + "TABLE_SCHEMA=DATABASE() AND TABLE_NAME='%s' AND " > + "COLUMN_KEY='PRI'", table_name); > + if (mysql_query(mysql, query_buff) || !(res= mysql_store_result(mysql)) || > + !(row= mysql_fetch_row(res))) > + { > + fprintf(stderr, "Warning: Couldn't determine if table %s has a " > + "primary key (%s). " > + "--innodb-optimize-keys may work inefficiently.\n", > + table_name, mysql_error(mysql)); > + goto cleanup; > + } > + > + has_pk= atoi(row[0]) > 0; > + > + cleanup: > + if (res) > + mysql_free_result(res); > + > + return has_pk; > +} > + > +/* > get_table_structure -- retrievs database structure, prints out corresponding > CREATE statement and fills out insert_pat if the table is the type we will > be dumping. > @@ -2659,6 +3029,9 @@ static uint get_table_structure(char *table, char *db, char *table_type, > result_table= quote_name(table, table_buff, 1); > opt_quoted_table= quote_name(table, table_buff2, 0); > > + if (opt_innodb_optimize_keys && !strcmp(table_type, "InnoDB")) > + has_pk= has_primary_key(table); > + see below > if (opt_order_by_primary) > order_by= primary_key_fields(result_table); > > @@ -2838,6 +3211,9 @@ static uint get_table_structure(char *table, char *db, char *table_type, > > row= mysql_fetch_row(result); > > + if (opt_innodb_optimize_keys && !strcmp(table_type, "InnoDB")) > + skip_secondary_keys(row[1], has_pk); > + Not that it makes a lot of difference, but I'd remove the previous hunk, the variable has_pk, and put everything here, as if (opt_innodb_optimize_keys && !strcmp(table_type, "InnoDB")) skip_secondary_keys(row[1], has_primary_key(table)); this removes one if(), one strcmp(), and doesn't invoke has_primary_key() (meaning, one SQL query less) unless all other conditions for skip_secondary_keys() are met. even better - don't do has_primary_key() at all, remove the function altogether, and look for "PRIMARY KEY" in the create string inside skip_secondary_keys(). > is_log_table= general_log_or_slow_log_tables(db, table); > if (is_log_table) > row[1]+= 13; /* strlen("CREATE TABLE ")= 13 */ Regards, Sergei

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Re: [Maria-developers] Features Wish-list in MariaDB 10.1.
by Kristian Nielsen 12 Jun '15

12 Jun '15

So my opinion on these below two points was requested, let's keep it on the public mailing list: > * Crash-Safe replication with filename and position (not depending on > GTIDs) > Something similar as what is described in the following link would > be good: > http://blog.booking.com/better_crash_safe_replication_for_mysql.html > * Have a way to avoid "SELECT binlog_gtid_pos" when a slave connect to > the master in MASTER_USE_GTID = no So my personal opinion on this is that I prefer to focus on improving the MariaDB GTID implementation. Considerable effort was invested into this, and the idea is that future development will focus on GTID mode, keeping non-GTID mode only as a backward compatibility. Significant effort was made to ensure that MariaDB GTID is usable for all existing use-cases of replication. For the first point, GTID replication is already crash-safe. For the second point, for GTID we in any case need a solution for locating GTID position quickly, otherwise GTID replication can have performance problems in case of frequent slave connects (and Jonas Oreland has promised a patch for this any day now ;-). And once this solution is in, the second point should be moot anyway. Of course, others may have a different opinion. For the second case, I suppose the easiest thing is just to remove the code that does SELECT binlog_gtid_pos() from the slave, if no-one cares about that functionality anyway... Hope this helps, - Kristian.

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[Maria-developers] 10.0 sprint: Please advise re MDEV-8109 unexpected CAST result
by Alexander Barkov 11 Jun '15

11 Jun '15

Hi Sergei, I'm thinking about what to do with MDEV-8109 unexpected CAST result. Observations: 1. An empty string in VALUES SET sql_mode='STRICT_ALL_TABLES'; DROP TABLE IF EXISTS t1; CREATE TABLE t1 (a DECIMAL); INSERT INTO t1 VALUES (''); ERROR 1292 (22007): Truncated incorrect DECIMAL value: '' This is OK. In strict mode INSERT with a bad value correctly returns the error. 2. CAST('' AS DECIMAL) SET sql_mode='STRICT_ALL_TABLES'; SELECT CAST('' AS DECIMAL); +---------------------+ | CAST('' AS DECIMAL) | +---------------------+ | 0 | +---------------------+ 1 row in set, 1 warning (0.00 sec) This is also OK. There are no tables involved, and CAST itself does not convert warnings to errors. 3. CAST('' AS DECIMAL) in VALUES: INSERT INTO t1 VALUES(CAST('' AS DECIMAL)); ERROR 1292 (22007): Truncated incorrect DECIMAL value: '' I think this is not OK. I wrote an explicit CAST, so I expect: - CAST to return 0 with a warning, like in #2 - INSERT to write 0 into the table normally, as I'm actually inserting the CAST result, which is 0. 4. COLUMN_GET(AS DECIMAL) in VALUES: SET @aaa = COLUMN_CREATE('price', ''); INSERT INTO t1 VALUES(COLUMN_GET(@aaa, 'price' AS DECIMAL)); ERROR 1918 (22007): Encountered illegal value '' when converting to DECIMAL This is also not OK. I wrote explicit column conversion to DECIMAL. I expect: - COLUMN_GET() to return 0 with a warning, like in #2 - INSERT to write 0 into the table normally, as I'm actually inserting the COLUMN_GET result, which is 0. Do you agree? Thanks.

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Re: [Maria-developers] MariaDB replication event generators?
by Kristian Nielsen 11 Jun '15

11 Jun '15

James Cheng <jcheng(a)tivo.com> writes: > The binlog stream has all the row data, but doesn't have > everything. It doesn't have column names, for example, or primary > keys, or character sets. Using the binlog for replication seems to > assume that you have a copy of the schema beforehand on the receiving > slave. It doesn't seem possible to replicate to a slave using only the > information in the binlogs. It is a common request to be able to do 3rd-party replication from mysqld. However, the replication protocol between master and slave servers was never designed as a public API, it is based on internal data formats and so on. So unfortunately, there does not exist currently a public API for doing external replication, at least not that I am aware of. The binlog stream _does_ have everything of course, eg. in the form of CREATE TABLE statements and so on. However, being internal to the server, they are not very easy to use by an external replication mechanism. - Kristian.

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Re: [Maria-developers] [Commits] 6ff2c0a: MDEV-5309 - RENAME TABLE does not check for existence of the table's engine
by Sergei Golubchik 10 Jun '15

10 Jun '15

Hi, Sergey! On Feb 09, svoj(a)mariadb.org wrote: > revision-id: 6ff2c0a05155f985484e23bd8611eb95f045907f > parent(s): f13939061d468a47985dee0268652a6fe2db7862 > committer: Sergey Vojtovich > branch nick: 10.1 > timestamp: 2015-02-09 16:12:00 +0400 > message: > > MDEV-5309 - RENAME TABLE does not check for existence of the table's engine > > When RENAME TABLE is executed, it apparently does not check whether the engine > is available (unlike ALTER TABLE .. RENAME, which does). It means that if the > engine in question was not loaded on some reason, the table might become > unusable, since the engine won't know about the change. > > With this patch RENAME TABLE fails if storage engine is not available. .... > diff --git a/sql/sql_table.cc b/sql/sql_table.cc > index e9a1ae9..f1096da 100644 > --- a/sql/sql_table.cc > +++ b/sql/sql_table.cc > @@ -5172,18 +5172,19 @@ bool mysql_create_table(THD *thd, TABLE_LIST *create_table, > error= my_errno; > (void) file->ha_create_partitioning_metadata(to, from, CHF_RENAME_FLAG); > } > - else if (!file || !(error=file->ha_rename_table(from_base, to_base))) > + else if (!file) > { > + error= ER_UNKNOWN_STORAGE_ENGINE; > + } > + else if (!(error= file->ha_rename_table(from_base, to_base))) > + { > if (!(flags & NO_FRM_RENAME) && rename_file_ext(from,to,reg_ext)) > { > error= my_errno; > - if (file) > - { > if (error == ENOENT) > error= 0; // this is ok if file->ha_rename_table() succeeded > else > file->ha_rename_table(to_base, from_base); // Restore old file name > - } > } > } > delete file; May be you'd rather fix it in the caller? Let's state that the first argument of mysql_rename_table() can never be NULL. While mysql_rename_table() is called in many places, the only place where it can actually get a NULL hton is sql_rename.cc, if ha_table_exists() returns hton=NULL. I'd add the check here and simplified mysql_rename_table(). Regards, Sergei

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