![]() ![]() Hot Network Questions How is current dropped through a step-up transformer, when current is dependent on resistance Forced mate from move one - what is this train of thought called. in mysql, add the column after the other column if exists. (As for SO vs dba.SE - There are a zillion and one questions on SO no human can even glance at all the questions, especially those that have only one tag. MySQL add new column on specific position. Please provide more info (as requested above) we may be able to help you find a not-too-painful way out of your predicament. ![]() And another 30GB file was being built, but disk space ran out. Since you mentioned 844MB and 3TB, I would guess that that setting was ON (or 1). The up method is used to add new tables, columns, or indexes to your database, while the down method. You may have that table so larger that the disk is full. A migration class contains two methods: up and down. This cursor object interacts with the MySQL server and can be used to perform operations such as execute SQL statements, fetch data and call procedures. Sometimes, we find that a piece of data that we did not maintain becomes important, and we need to add a new table column to the database. Could it be that that is a separate disk partition, and that partition is too small?Īt the time of running the Alter, what was the value of innodb_file_per_table? If it was OFF (or 0), then you have a nasty problem - ibdata1 would be expanded by the 30GB, and not shrunk back. To add a column to a MySQL table in Python, first establish a connection with the database server. It may be that that space needs to be in the "tmpdir". In your case, there needed to be about 30GB free on disk to perform the Alter. The "copy" method needs disk space to make a full copy of the table, then it does something like RENAME TABLE to swap it into place. Although this answers your question, Im not sure if it is the best approach to your overall problem. SELECT JobNo ,Prepared1 ,Prepared2 FROM test SELECT COUNT (CASE WHEN Prepared1 >1 THEN 1 END) + COUNT (CASE WHEN Prepared2 >1 THEN 1 END) as Done FROM test GROUP BY JobNo. (Please provide the version of MySQL and the text of the ALTER.) create table t ( id int autoincrement primary key, x int, t timestamp default now (), tt time generated always as (time (t)) ) That is, add a timestamp column and then extract the time. I want to display the result of my query as a new column, this is my code but it shows to be in 2 tables. It seems that this option was either not available due to using an old version or the complexity of the ALTER. Certain optimizations that avoid needing to copy the table.Copy the table over, making the change as it goes.It is not wise to raise either of those above 1% of RAM.ĪLTER works in one of two ways, depending on version and the specifics of the query. ![]() Tmp_table_size and max_heap_table_size are useful for certain complex SELECTs, not for ALTER. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |