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8
votes
Is there a way to hint to query optimizer to MySQL which constraints should be done first?
I have rather bad news for you in this regard
MySQL Query Optimizer tends to stray away for further optimization once it sees a FULLTEXT index. … Optimizer detects a FULLTEXT search along with the conjunction AND followed by an expression within the same WHERE clause (thus, the same level of evaluation within an EXPLAIN plan), the MySQL Query Optimizer …
6
votes
Accepted
slow query with fulltext and left join
The problem lies in the fact that MySQL's Query Optimizer gets very confused when used in conjunction with other tables in an EXPLAIN plan's compliation. … optimization (Jan 26, 2012)
MySQL EXPLAIN doesn't show 'use index' for FULLTEXT (May 07, 2012)
My suggestion: Try Refactoring the Query By Getting the FULLTEXT Search to occur before JOINs
SELECT * …
5
votes
Accepted
Fulltext search using multiple indexes
Unfortunately, this is how MySQL Query Optimizer treats FULLTEXT indexes. When a MATCH clause is the only clause in the WHERE, the index will be used. … I wrote about this behavior before in Mysql fulltext search my.cnf optimization
SUGGESTION : Rewrite the query as the union of two FULLTEXT searches
SELECT * FROM content
WHERE MATCH(a, b, c) AGAINST …
9
votes
Accepted
Mysql fulltext search my.cnf optimization
QUERY
Here is a little known fact about MySQL queries using a Full Table Index: There are occasions when the MySQL Query Optimizer stops using FULLTEXT indexes altogether and perform full table scans. … The MySQL Query optimizer basically barfed at it. …
2
votes
Why is LIKE more than 4x faster than MATCH...AGAINST on a FULLTEXT index in MySQL?
Every time there is a query involving a FULLTEXT index, the MySQL Query Optimizer tends to whack the query into a full table scan. I have seen this over the years. … As I mentioend earlier, using FULLTEXT indexes tends to nullify any benefits attempted and contributed by the MySQL Query Optimizer. …
2
votes
Mysql fulltext boolean ignore phrase
I tend to be a little conservative and cautious when using FULLTEXT indexes because FULLTEXT indexes has a nasty habit of playing head games with the MySQL Query Optimizer. … Go with the first query.
Give it a Try !!! …
4
votes
Less restrictive query return less result due to simple removing one additional constraint
The FULLTEXT index acts very funny with regard to the MySQL Query Optimizer. … my.cnf optimization (Jan 26, 2012)
MySQL EXPLAIN doesn't show 'use index' for FULLTEXT (May 07, 2012)
Try refactoring your first query so that the FULLTEXT clause and the Spatial clause are not performed …
2
votes
MySQL EXPLAIN doesn't show 'use index' for FULLTEXT
Query Optimizer will not use the index and will go with a table scan or an index scan instead. … FULLTEXT indexes tends to get thrown the Query Optimizer under the bus at the most inconvenient times. I wrote about that back in Jan 26, 2012. …
4
votes
Accepted
How to make a FULLTEXT search with ORDER BY fast?
The Query Optimizer's reaction to a FULLTEXT index. Why ?
(Now imagine the start of a STAR WARS movie with scrolling words...) … A very long time ago, I discovered that FULLTEXT indexes will nullify the MySQL Query Optimizer's use of other indexes
Jun 10, 2011 : Mysql fulltext boolean ignore phrase
Oct 25, 2011 : FULLTEXT index …
4
votes
Accepted
FULLTEXT index ignored in BOOLEAN MODE with 'number of words' conditional
The MySQL Query Optimizer tends to get sidetracked very easily when using a FULLTEXT index.
I also have very good news for you.
I wrote about this in StackOverflow on how to get around it. … You may have to nest your original query in a subquery and return the MATCH function as a column. Then, evaluate the MATCH column outside of the subquery. …
2
votes
How can I rewrite the following removing the date_format function?
Leaving the t1.when on the left side of the comparison (left side of the equal sign) obligates the MySQL Query Optimizer to try using the index. … other posts going back to 2011 that discuss how searching a FULLTEXT index cause the MySQL Query Optimizer to stop using other indexes (since you have to use the MATCH function on the left side). …
6
votes
Accepted
Multi-Column Full Text Search Going Very Slow
PROBLEM
From the posts in your question, I see 3 FULLTEXT indexes. There is one for each column.
Why did the query work at all ? MySQL worked with whatever it had. … That's what the MySQL Query optimizer decided on. …
1
vote
Joining two Mysql VIEWs takes a very long time
While FULLTEXT index searches do work, the MySQL Query optimizer tends to suggest full table scans if you do not express the query properly. … How do I optimize this?
Given the information I just mentioned let's take your query and refactor it to handle the FULLTEXT and stilldo a good join. …
1
vote
Is inserting in a MySQL table with a Full-Text index really slow?
If it calls for a FULLTEXT index, make sure you have the with combination of columns. You will also need to focus on structuring your queries so that using a FULLTEXT index is worth it. … Sometimes, the MySQL Query Optimizer tends to butt heads with FULLTEXT indexes and ends up ignoring them unless you design the query properly. …
6
votes
Full text search results in a large amount of time spent in 'FULLTEXT initialization'
Status : No Feedback
SELECT query hang in state FULLTEXT initialization
Oct 17, 2014
MySQL 5.6.19
Status : Won't Fix
Since the MySQL Documentation is very terse on this thread state
FULLTEXT … I have recommended this many times before
May 14, 2012 : slow query with fulltext and left join
Mar 18, 2012 : Why is LIKE more than 4x faster than MATCH...AGAINST on a FULLTEXT index in MySQL? …