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21h
comment How do you calculate how much hardware resources you need for a database?
Addenda 1 and 2 added
23h
revised How do you calculate how much hardware resources you need for a database?
back to question
23h
revised How do you calculate how much hardware resources you need for a database?
Add tuning analysis
1d
comment Insert but Don't Commit MySql
Another potential 'badness' in burning ids is when you burn them so fast that the integers threaten to overflow. Once I got in trouble with SMALLINT UNSIGNED (65K max) and "I'll never need more than a few thousand". But the code was burning ids.
1d
comment Is it safe to disable InnoDB doublewrite buffering when setting Innodb_page_size = filesystem page size?
Valid question. I don't know enough about ext4 (or any other fs) to answer at that level. I would guess that "consumer grade" hardware could have partial writes, but "enterprise" grade might protect against that. It's probably the disk controller's choice, not ext4. Well, some filesystems have "journalling", which may protect you. (InnoDB's "doublewrite buffer" protects at the InnoDB level.)
2d
comment MySQL restore old backup over new data
If your PK is AUTO_INCREMENT and you cannot use it to match up records, then ignore it. Instead use some UNIQUE key.
2d
comment MySQL restore old backup over new data
Step 2 JOINs on the PK to see the data differences. UPDATE good JOIN delta USING (pk) SET good.x = delta.x, ...;
2d
answered Mysql Slow when join query running increaed
2d
revised How do you calculate how much hardware resources you need for a database?
correct typo
2d
comment Is it safe to disable InnoDB doublewrite buffering when setting Innodb_page_size = filesystem page size?
Is it really 16K on the disk? Or is it pretending, and still writing a bunch of 512-byte sectors on the drive? Virident, for example had a capacitor to 'guarantee' that any write that was started would be finished. Since SSDs have other stuff that needs to persist, there is a good chance that all of them can write 16K atomically. But -- see if they are willing to claim it.
2d
answered compare results between two select queries mysql
2d
comment Unique Index/Constraint with multiple columns, one column is nullable
Yeah, build an extra column for uniqueness, and populate with an algorithm that suitably ignores (or turns into "") any NULLs.
2d
answered Insert but Don't Commit MySql
2d
answered MySQL restore old backup over new data
2d
answered Remove duplicates from multiple joins
Aug
25
comment Mysql Slow when join query running increaed
Please show us the entire query, plus SHOW CREATE TABLE. May need to use SHOW FULL PROCESSLIST;.
Aug
25
comment MySQL drops every connection, even locally
Are you connecting to localhost? Or thru TCP/IP?
Aug
25
comment MySQL drops every connection, even locally
Compare SHOW GLOBAL VARIABLES LIKE '%timeout%'; with SHOW SESSION VARIABLES LIKE '%timeout%';
Aug
25
answered MySQL adds broken comment script after each line
Aug
25
comment Finding differences between two tables takes too long
What is the value of innodb_buffer_pool_size?