Slow Query Wile Using Indexes
i am having a problem with a aparently normal query, i am using indexes and it is still very slow, as the table grows biger and biger i am afraid the system cant hadle it...
Here is the table data: ....
View Complete Forum Thread with Replies
Related Forum Messages:
Fast SELECTs Versus Slow INSERTs With Indexes
I run a MySQL database using phpMyAdmin interfaced with an application written in C++, and most of my nine database tables have 500,000 - 2,000,000 records in them. These tables also have about five-to-six indexes each. This makes working with the C++ application extremely fast, which is nice. Any SELECT statements can be run in less than a second, and I'm very happy. The problem comes when I have to insert new records into the tables. Every morning, I am received a pipe-separated .txt file of the previous day's new records (about 500 - 1,000) that I have to insert into the tables using my C++ application. Well, this takes an excruciatingly long time (almost an hour, actually) and I need to find some way to make it run faster. I am thinking of several options here:
View Replies !
Multiple Indexes In One Query
I do a query like this on a couple million rows and it's too slow. SELECT `title`,`link`,`description` FROM `files` WHERE `spam` =0 AND `porn` = 0 AND `lastvisit` > 0 AND MATCH (`host`,`path`,`title`,`description`) AGAINST ('some query') I know it's using my FULLTEXT index on host, path, etc. I have another INDEX index on spam,porn, and lastvisit as well. Is it using this index already? If not is there a way to get it to use both indexes together?
View Replies !
Pagination W/1 Query + How To Use Query With Indexes
i'm asking 2 questions in 1 thread because i don't wanna take up too much room, hopefully no one will mind. i have mysql 4.1.10 1) i want to find all the rows that were edited this month. the query i currently have ( MONTH(CURDATE()) = MONTH(date) ) doesn't use indexes. how can i manipulate it so i can take advantage of indexes. 2) this is something i've always wondered, but usually just assumed was not possible. if i am listing some results, say 20 per page, how can i get both the total number of results as well as the 20 items required for that specific page. say there are 2 million total results, so grabbing them all and showing just 20 is not an option. if this is not possible what is the most efficient way of making both queries?
View Replies !
Indexes To Speed Up A Duplicates Query.
OK, say you're trying to find all the non-exact duplicates in a table, and especially do it with a single query, so that the check can be part of a user interface. Then naturally you're going to have a slow query, because it has to compare every row with every other row. You ought to be able to cut out exactly half of the records in the second table, by just saying: SELECT * FROM TABLE LEFT JOIN users dups ON users.created<dups.created But I can't get MySQL to use the index I have on 'created' (same results for integer-primary key, & a string field). My best guess why not is that (according to the manual) "MySQL will not use an index when ... the use of the index would require MySQL to access more than 30% of the rows in the table" - is this the reason? Another option: say that I thought that my duplicates will always have the same letter in their surname, then I could make an index on the first letter of the surname, and make the join just on *that*. This should make the number of rows needed up to 26 times less, right? But exactly how is this done? MySQL won't use my index on the following query: SELECT * FROM TABLE LEFT JOIN users dups ON SUBSTRING(users.name,0,1)=SUBSTRING(dups.name,0,1)
View Replies !
Slow Query Log
my slow log is catching a slow query, however the timestamp for the query is "0". I also placed a timestamp on the query to echo out to the results page, and it is about 4 thousands of a second. Why is it showing in the slow log?
View Replies !
Slow Query Using NOT IN
I am migrating a MSSQL server to MySQL. I know the following SQL is valid for both servers, but MSSQL finishes execution of the query almost instantly, and MySQL has been running the query for the past ten minutes and still is not finished. There is basically the same amount of data in each database. Does anyone know ....
View Replies !
Slow Query
i have this query on a website/webapp that has expanded beyond all expectation. It now takes nearly 30secs to return results from the database SELECT cl_t.Client_ID, Buyer_1_Title, Buyer_1_Prename, Buyer_1_Surname, Tel_No, Mob_No, Buyer_2_Title, Buyer_2_Prename, Buyer_2_Surname, Email_Add, Price_Max, MAX(activity_t.Date) AS lastcomm FROM cl_t INNER JOIN cl_want_t ON cl_t.Client_ID = cl_want_t.Client_ID AND Agency_Code ='$agencyloggedincode' AND Deleted = 'N' LEFT JOIN activity_t ON Buy_Sell = 'B' AND Ref_No = cl_t.Client_ID WHERE cl_t.Sales_Agent_ID = $agentid GROUP BY cl_t.Client_ID ORDER BY $order The problem is the call to MAX(activity_t.Date) AS lastcomm activity_t holds all known contact with all known clients and as such is a very large table, the call to search through all of these records and return only the date of the last entry for this client is taking the time. If I remove this from the query I get results in 3 seconds. I have indexing on activity_t.Date & activity_t.Ref_No Question, is there a way of doing this quicker within the table I already have, or should I create another table that just holds the last update date for each client, and get the date from this much smaller table.
View Replies !
Why Is This Query Too Slow?
I find this query to be exceptionally slow(around 2.5 seconds), could some tell me why this is so? MySQL SELECT st.profile_views,count( DISTINCT p.ID ) news_submitted, count( DISTINCT pv.ID ) news_voted, count( DISTINCT pcom.ID ) news_commented, u.joined, u.weight FROM users u LEFT JOIN posts p ON p.submitted_user_id = u.user_id LEFT JOIN post_votes pv ON pv.user_id = u.user_id LEFT JOIN post_comments pcom ON pcom.user_id = u.user_id LEFT JOIN stats st ON st.user_id=u.user_id WHERE u.user_id='john' GROUP BY u.user_id I traced the cause to this line count( DISTINCT p.ID ) news_submitted (from LEFT JOIN posts p ON p.submitted_user_id=u.user_id) But when i execute something like this MySQL SELECT count( DISTINCT p.ID ) news_submitted FROM posts WHERE submitted_user_id='john' it is quite fast (around 0.03 seconds) So why does it slow down when i'm joining the above query with 3 other tables ? Should i use INTEGER for user_id instead of string like 'john'?
View Replies !
Slow Query->Efficient Query
I have a query that is running really slow !!!! I have joined on Key fields and indexed the tables fully but it is still solw. -------------------------------------------- select d.id, a.signed, u.Forename, u.Surname, d.paid, p.date, d.payment, p.amount, d.acctual from details d join poten a on a.id = d.id left join recieved p on d.id = p.id left join users u on a.signed = u.userid where d.paid > '01-Dec-2005' and d.authorrceived is not null and d.authorrefused is null and ((d.payment starting 'E' or d.payment starting 'e') or (d.payment starting 'Q' or d.payment starting 'q' and p.target = '500')) order by d.paid, a.signed, d.id
View Replies !
Slow Query Log Not Staying On
I'm running MySQL 4.0.16 on Windows 2003. I just added the mysqld-nt command line option to enable the slow query log, started MySQL, and the option showed up as turned on. Then later I restarted the server, and the slow query log option went back to being turned off. Is this a Windows problem in not remembering the service parameter? Has anyone else seen this?
View Replies !
View Slow Query Log
I searched here, google and MySQL docs but did not find an answer. I'm using MySQL-Front from a Windows platform to administer a remote database. The remote server doesn't have phpMyAdmin or anything like that. MySQL-Front reports 133 Slow Queries and an average of 15 queries per second. But I dont' know how get more information than that.
View Replies !
Slow Query Log Files
I have edited my.ini file to create a file called slow queries. My problem is that when the server starts up i do not get a full list of all slow queries. Is there anything else i need to change? How else can i come about in getting all queries that took a long time to execute? im using mySQL 5.0.9.
View Replies !
Query Execution Too Slow!
I have migrated from MySQL 4.1.22 to MySQL 5.0.45. Many of the queries that were working on my old server is working too slow in my new server(MySQL version 5.0.45). I am not aware why is this happening. Actually there is no error message or query failing. The query is executing, but the time taking to execute the query is too long. This problem is not occurring for all queirs, but only for some complex queires, that is queries with Left Join or Right Join, Group By etc. I have also checked the MySQL details through SSH(that is by mysql> SHOW VARIABLES;) Now one thing I found is there is lot of difference in key_buffer_size, table_cache, join_buffer_size, read_buffer_size, read_rnd_buffer_size , table_cache etc between my new server MySQL and old server MySQL. Will this be the reason for query execution taking too much time. Can any one guide me why this is happening. The striking thing is that these quires was working very much fine and faster in my old server.
View Replies !
Recycling The Slow-query.log
Am using v5.0.22. log-slow-queries=/var/lib/mysql/log/slow-query.log, but this has grown to over 4GB. Can this slow-query.log file by recycled without starting the server? Meaning can I do the following: mv slow-query.log slow-query.OLD.log, followed by a touch slow-query.log WHILE the server is running?
View Replies !
Slow Update Query
I have about 2000 update queries to do, which takes about 1 hr on 250,000 rows. My table is getting kinda slow here is the query i am using UPDATE nametable SET sectionname = replace(sectionname,'".$oldsec."','".$sec."'), categoryname = replace(categoryname,'".$oldcat."','".$cat."'), published=Ƈ' where sectionname='".$oldsec."' and categoryname='".$oldcat."' ; I am wondering if the same thing is possible with an insert... on duplicate key statement? I cant seem to get the insert statement to work, but not even sure whether it is appropriate. With this query I am basically finding and replacing some columns based upon another table (within the php script I am using)
View Replies !
Slow Query Execution
Right now I am fazing one issue which is getting hell out of me. I am explaining the issues step by step. 1.I have one site running from last 3 years with large database and there is one main table which has maximum load. 2.Now, I have redesigned the site with lots of changes within this table too. 3.The problem is that the server is same, queries are same but output in the new database is taking 50 times more execution time. 4.I also just copy paste the table, and fire the same query... Strange even that is not working... Is it something where newly added table or database is having issues in the server? I have tried all, compared the structures of the data and table but still the query result is too slow on live testing sever. While same query in main site of same server is running perfectly.
View Replies !
Slow Query Issue
I'm getting issues with slow queries being generated by a table in my database for my app, this query is consistently generating an entry in the slow query log: SQL Code: # Query_time: 2 Lock_time: 0 Rows_sent: 27 Rows_examined: 958SELECT `p_id` FROM `products` LEFT JOIN `products_images` ON (`p_id` = `pi_pid`) WHERE `pi_image_mime` IS NULL AND `p_archived` = '0' GROUP BY `p_id`; an explain query generates this: 1 SIMPLE ls_products ref p_archived p_archived 1 const 866 Using where; Using mysqlorary; Using filesort 1 SIMPLE ls_products_images ref pi_pid pi_pid 4 shop.ls_products.p_id 12 Using where; Not exists and a desc generates this: SQL Code: pi_id  int(11)   NO   PRI   NULL  AUTO_INCREMENT     pi_pid   int(11)   NO  MUL  0        pi_label  varchar(255)  NO               pi_primary_image  tinyint(1)   NO      0         pi_sort_order  int(11)  NO      0       pi_micro_blob  mediumblob   NO                pi_thumb_blob  mediumblob  NO             pi_large_blob  mediumblob  NO             pi_zoom_blob  mediumblob   NO                pi_image_mime  varchar(25)  NO               pi_date_added  datetime   NO     0000-00-00 00:00:00        pi_filename   varchar(50)   NO                pi_image_label   varchar(255)   NO
View Replies !
Query With 3.3million Rows Is Slow?
I'm not that great with MySQL...so I was hoping someone could help me out. The query I'm running is too slow...can anyone tell me what I can do to speed it up..if I can at all? I was wondering if because ZipListMatrix has 3.3 million rows that 8 seconds is all the faster it's going to be. Any help is greatly appreciated! I have already "optimized" the tables.
View Replies !
Server Slow When Exec Following Query
i try to tweak mysql server but the process still very slow to exec o following query exec time 2min for 11k row in two table update uploaded,uploaded_job set uploaded.export = 'yes' WHERE uploaded.work_order =uploaded_job.work_order and uploaded_job.claim_status IS NULL i had try indexing and optimise my database result still the same.
View Replies !
Federated Tables Slow? (like 4.5 Hrs For A Query)
I've got a problem with federated tables. I'm using MySQL 5.1 (with InnoDB as the default table type) on a Win2K server, on which I've got four federated tables pointing at four MyISAM tables on a MySQL 4.1.11 server. Of the four tables, three of them run just fine, and I can retrieve data quickly with no problems. The fourth is a sheer pig. While they have different columns, all four tables are roughly as complex as each other, all having the same features and developed by the same team. The most obvious difference, and what I suspect might be the problem, is that the first three tables have between 150 and 1,000 records, the fourth table has closer to 15,000. Still, there isn't that much lag when I'm pulling from the smaller tables, and the lag is really serious when I'm pulling from the larger one; I ran three queries last night to test, and I could pull data from the smaller tables in about 5 minutes, but the larger table took 4.5 hours- possibly because it was joined with two other tables, but the joins on the smaller tables didn't cause this kind of problem. The second obvious difference is the fact that I'm pulling from a MyISAM table into a federated table... from which I would like to store into an InnoDB table, but it ends up timing out quite a bit. Connecting to the database I've federated to isn't a problem. It responds to a PHP frontend lightning-fast. It's just my federated tables that suck so bad. I wouldn't even use federated tables, but I need to pull from the MyISAM database for storing historical records of inventory. What am I doing wrong, and what can I do to speed things up?
View Replies !
Slow Inefficent Query (FIXED)
I have this query which pulls members from a table of 1200 members details, filtering out those without and email address and those that don't want Newsletters, and also any whose email address exists in a second table (emails that have hard bounced previously) My first attempt took an age and returned about 10,000 members, clearly loads of repeated rows My 'final' attempt with a DISTINCT shoved in works perfectly but is really slow, PHPAdmin says it takes 1.1s but on the website the data doesn't appear for over 30s, all the other sundry queries on the same table work nice and quick on the same website using the same php to generate the table of results The googling I've done suggests (to me) that there's nothing wrong with the query but I suspect that there's far too much checking of fields going on from the pre DISTINCT query's results ....
View Replies !
Mysql 5.0 - Using My.cnf - Unix / Slow-query-log
I installed mysql 5.0 and need to set up slow-query-log and other logging options. Here is what I did. But I dont see it working yet. 1. cd /var/db/mysql 2. chown mysql slowquery.log 3. touch /usr/local/etc/my.cnf 4. chown mysql /usr/local/etc/my.cnf vi my.cnf [mysqld_safe] -u mysql --log-slow-queries=/var/db/mysql/slowquery.log so now when I type: mysqladmin shutdown and than mysqld_safe & my sql restarts but the log files are not being used. also - how do I know if my my.cnf is being used at all?
View Replies !
Turning On Slow Query Logging?
Background: I paid a young admin set me up on a database server. He installed the basic I needed for the server...at my request...No Cpanel...mysql and apache and some tight security w/o even a domain name to SSH into. Unfortunately, he's a busy kid, and teens sometimes don't realize that people depend on them...and well, I can't really seem to get him to do much so I gave up and figured it's a good way to force me to learn all this myself... Well anyway, now I want to turn on Slow Query logging. But before I do that, I need to know how MySQL is running. Is SQLogging turned on already? Where is it logging to? So first thing I want to look up is, when the server is rebooted, what's the command to restart mysql? No clue. How do I change the setting? And of course, the server is production, so when I make the change, it needs to be quick, it needs to be smooth, and I need to be able to roll back to the previous config if necessary. I'm running Redhat Enterprise.
View Replies !
Slow Query W/ Join & Ordering
I am trying to figure out why I have a hugely slow query (~2 seconds in my testing environment). Details are below: It involves two tables, products and vendors. Products is a huge table, so I will only include the (ostensibly!) relevant fields in its description: CREATE TABLE `products` ( `id` int(11) NOT NULL auto_increment, `vendor_id` smallint(6) NOT NULL default Ɔ', `product_code` varchar(255) NOT NULL default '', `internal_name` varchar(255) NOT NULL default '', `lastmodified` timestamp NOT NULL default CURRENT_TIMESTAMP on update CURRENT_TIMESTAMP, PRIMARY KEY (`id`), UNIQUE KEY `product_code` (`product_code`), KEY `vendor_id` (`vendor_id`) ) ENGINE=MyISAM; Vendors are much more straightforward: CREATE TABLE `vendors` ( `id` smallint(6) NOT NULL auto_increment, `name` varchar(255) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM; The following query executes in no MORE than 0.01 seconds: SELECT DISTINCT p.id , p.product_code , unix_timestamp(p.lastmodified) as lastmodified , p.internal_name FROM products as p ORDER BY p.product_code ASC LIMIT 0, 30; And has the following attributes: +----+-------------+-------+-------+---------------+--------------+---------+------+-------+-----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+---------------+--------------+---------+------+-------+-----------------+ | 1 | SIMPLE | p | index | NULL | product_code | 257 | NULL | 25124 | Using temporary | +----+-------------+-------+-------+---------------+--------------+---------+------+-------+-----------------+ When I join with the vendors table, so that I can fetch the vendor's name for each product, I use the following query, which takes about 1.88 seconds: SELECT DISTINCT p.id , p.product_code , unix_timestamp(p.lastmodified) as lastmodified , p.internal_name , v.name as vendor_name FROM products as p LEFT JOIN vendors as v ON v.id=p.vendor_id ORDER BY p.product_code ASC LIMIT 0, 30; It has the following characteristics: +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+---------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+---------------------------------+ | 1 | SIMPLE | p | ALL | NULL | NULL | NULL | NULL | 25124 | Using temporary; Using filesort | | 1 | SIMPLE | v | eq_ref | PRIMARY | PRIMARY | 2 | te_inventory.p.vendor_id | 1 | | +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+---------------------------------+ Note the addition of the filesort. I'm unhappy enough about the temporary, which I don't really understand, but the filesort is, I'm fairly sure, killing me. Closer investigation (or maybe just common sense if you aren't a MySQL newbie like me) shows that the ORDER BY clause is responsible, for when I join without the ORDER BY, my query time goes back down to 0.01 seconds or so: mysql> explain SELECT DISTINCT p.id -> , p.product_code -> , unix_timestamp(p.lastmodified) as lastmodified -> , p.internal_name -> , v.name as vendor_name -> FROM products as p -> LEFT JOIN vendors as v ON v.id=p.vendor_id -> LIMIT 0,30; +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+-----------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+-----------------+ | 1 | SIMPLE | p | ALL | NULL | NULL | NULL | NULL | 25124 | Using temporary | | 1 | SIMPLE | v | eq_ref | PRIMARY | PRIMARY | 2 | te_inventory.p.vendor_id | 1 | | +----+-------------+-------+--------+---------------+---------+---------+--------------------------+-------+-----------------+ Any clues on how I can get the execution time to go down when I am sorting? I'm also curious why MySQL is using a temporary table,
View Replies !
Help Rewriting A Slow Phpbb Query
I have a "glance" or "Recent Topics" list on my forums that have become fairly complex. I modified an already feature rich glance mod to allow users to select individual forums to exclude from showing topics in the list. As well when users are members of certain forum groups, they see topics from the group forum in the list, and they are highlighted a different colour. The main SQL query to create the list often is showing up in the MySQL Slow_query log and I'm pretty sure is the main cause for the page loading slow. I am no mysql Guru, so I thought I would seek the advice of some to improve or totaly rewrite this slow query. PHP $sql = "SELECT f.forum_id, f.forum_name, t.topic_title, t.topic_id, t.topic_last_post_id, t.topic_poster, t.topic_views, t.topic_replies, t.topic_type, p2.post_time, p2.poster_id, u.username as last_username, u2.username as author_username FROM " . FORUMS_TABLE . " f, " . POSTS_TABLE . " p, " . TOPICS_TABLE . " t, " . POSTS_TABLE . " p2, " . USERS_TABLE . " u, " . USERS_TABLE . " u2 WHERE f.forum_id NOT IN (" . $forumsignore . $glance_recent_ignore . ") AND t.forum_id = f.forum_id AND p.post_id = t.topic_first_post_id AND p2.post_id = t.topic_last_post_id AND t.topic_moved_id = 0 AND p2.poster_id = u.user_id AND t.topic_poster = u2.user_id ORDER BY t.topic_last_post_id DESC"; $sql .= ($glance_recent_offset) ? " LIMIT " . $glance_recent_offset . ", " . $glance_num_recent : " LIMIT " . $glance_num_recent; The "NOT IN" list varies per user, but here is an example: NOT IN (77,75,76,25,26,37,63,64,66,67,67,1,25,26,37,70,28,75,76,78)
View Replies !
Can't Turn On Slow Query Logging
long_query_time = 1 log-slow-queries = /var/lib/mysql/slow_queries.log Is the above syntax not correct for enabling slow query logging? All examples I've seen have the dashes in the second variable and underscores in the first. When I restart MySQL with those lines in my.cnf, it fails to start, but writes nothing to its error log. /var/lib/mysql/slow_queries.log exists, is owned by mysql, and has read/write permission.
View Replies !
815,000+ Records, DB Table Query Too Slow
I have a database table with about 815,000 records in it, each record containing the source of individual webpages (with all the tags and multiple spacing stripped out leaving just the words). At first my match boolean queries were fine but once I got to around 100,000+ records it became too slow to use for a web-based search tool. I was able to separate the data into 10 tables and then use AJAX to run the match query on all 10 tables at the same time and that has increased performance. My question is, is it possible for me to increase the performance for the 1 table some how instead of resorting to separating the data into multiple tables? Is MySQL the right DB for this kind of setup, would MSSQL or PostgreSQL perform better for larger sets of data? I'm not sure how MySQL 5 clustering works,
View Replies !
Do Parallel Inserts And Selects Slow Down A Query?
I've been facing problems with a query which I think is relatively well optimized but has been performing really slow as of late as the size of the table has increased to more than 1GB. The MyISAM table is updated every few seconds, only a few rows, and a different set of rows are selected every few seconds.Wwould that cause a slowdown and if so, what is the solution?
View Replies !
Large Table, Slow Query Question
I have a table with ~800,000 records. I need to grab random rows from the table based on certain criteria. The problem is that average lowest subset to grab the random row is around 200k. Here is what I'm trying to do: There are 4 columns: data,n1,n2, and n3. I need to get the value of the data column based on criteria using the n1-n3 columns. The most common query is SELECT data FROM table WHERE n1 = ? The problem is that n1 can be only 1 of 5 possiblities. When the table is finished being populated there will be roughly 1.5 million records and 250k for each value of n1. Of course, I have an index on each n column. Right now with just the 800k records it can take over a second, sometimes multiple seconds to run the following in order to get a random row from that subset: SELECT COUNT(1) AS total FROM table WHERE n1 = 3; index = random number from 1 to total SELECT data FROM table WHERE n1 = 3 LIMIT index,1; How can I speed this up? I need it to take less than half a second if possible. Thank you.
View Replies !
Speed Up Query, Order By Column Is Too Slow!
I have a query that takes ages: SELECT tbl1.a, tbl2.b MATCH (tbl1.a) AGAINST ( 'someValue'IN BOOLEAN MODE ) AS score FROM `a` , `b` WHERE tbl2.b = 'someRestriction' ORDER BY score DESC, b.tbl1 DESC LIMIT 20 but because there are thousands of rows it takes ages to do both of the orders, however just : ORDER BY score LIMIT 20 -- is really quick and : ORDER BY b.tbl1 LIMIT 20 -- is really slow is it possible rearrange a constantly updated database so that its naturally ordered by b.tbl1 (so there will be no need to do the ORDER BY b.tbl1 query each time), or are there any other methods to speed this up (putting it all in one table instead of 2, is that significant?)
View Replies !
Slow Query Execution With Strange Issue
Right now I am fazing one issue which is getting hell out of me. I am explaining the issues step by step. 1.I have one site running from last 3 years with large database and there is one main table which has maximum load. 2.Now, I have redesigned the site with lots of changes within this table too. 3.the problem is that the server is same, queries are same but output in the new database is taking 50 times more time. I have tried all, compared the structures of the data and table but still the query result is too slow on live testing sever. While same query in main site of same server is running perfectly. Have any one fazed such and issue? Please help me out of the situation as site is ready but I m not able to put new version live.
View Replies !
Slow SELECT Query INNODB Table
I have a couple hundred connections doing "SELECT [Char36 Field], [LongLong Field], [Long Field] FROM [Connection Specific Table] WHERE [NonIndexed VarChar36 Field]=[Value]". Notice that the table the select statement is being called on is unique to each connection. These tables have less than 10000 records, but this statement can sometimes take over an hour to execute. It is an INNODB table.
View Replies !
VER VERY VERY Slow MySQL Query HELP URGENTLY NEEDED
I have the following MySQL query, but it is VERY VERY slow and seems to be crashing the server. There are 300,000+ records in the 'tracker' table. SELECT sites.*, SUM(if(tracker.type='view',1,0)) AS numberOfViews, SUM(if(tracker.type='click',1,0)) AS numberOfClicks, SUM(tracker.revenue) AS totalRevenue FROM sites LEFT JOIN tracker ON tracker.site_id = sites.id GROUP BY sites.id ORDER BY sites.domain_name
View Replies !
Why Does The Slow Query Log Show More Rows Than Exist?
# Time: 070528 17:14:57 # User@Host: counter[counter] @ localhost [] # Query_time: 3 Lock_time: 0 Rows_sent: 7 Rows_examined: 120647 SELECT SQL_CACHE `webpageUrl`, `webpageName`, COUNT(*) AS `count`, (COUNT(*) / (SELECT COUNT(*) FROM _1_log)) AS `pct` FROM _1_log GROUP BY `webpageUrl` ORDER BY `count` DESC LIMIT 7; mysql> select count(*) from _1_log; +----------+ | count(*) | +----------+ | 111824 | +----------+ 1 row in set (0.00 sec)
View Replies !
Slow Execution For A Left Outer Join Query
Whats likely to be the cause of slow execution for a left outer join query? The original query joins three tables but even if I narrow it down to one it still takes a long time to execute. $query = "select distinct materials.* from materials"; $query .= " left outer join materials_products on materials.material_id = materials_products.material_id"; There's 914 rows in the materials table and 1348 row in the materials_products table Is it likely to take a long time for this amount of data or is there likely to be a problem in the table(s) set up or query?
View Replies !
What Are Indexes?
What exactly are indexes? are they like Foriegn Keys? How do you make Foriegn Keys? How would you go about specifying the primary key link to the foriegn key? whats a good situation when indexes are most needed?
View Replies !
Two Indexes
I have a DB made up o three tables. I created a multi-column index called idx on (table1.id, table2.id). I also would like to create an index idtot on (table1.id,table2.id, table3.id) and an index idp on (table1.id, table2.id). First of all I would like to know if this is possible. If so, when I make a query like "select table1.id from table1,table3 where table1.id=table3.id", MySQL automatically chooses the right index idp to make the search, or do I have to specify it? (and if so, how?).
View Replies !
Many-to-many Indexes
You have a many-to-many between two tables. One method (which I use, and which apparently is seen as a good method) is to use a linking / joining table. Just a table with two columns, having IDfromTable1 and IDfromTable2. Now, what is the best way to index this 'link' table? Table1 and Table2 will have a primary key index on their unique IDs, and those IDs will have several matching values each on the 'link' table. Is it better to create an index on each column in the 'link' table? Or create an index which uses both columns? I get that using both columns would give me the ability to have a unique key, but performance-wise, etc. which is the better option? Tables are MyISAM.
View Replies !
Indexes
I have a few books on mysql and have succesfully now transferred all my records over from ms access. everything does work ok but it searches are a little slow (even slower than ms access which is why i moved in the first place). I have 17 tables in the database and it is all in third normal form. I have correct primary keys on all. I think indexes is the prolem here. I have added a few but i am unsure about how many to add and also about updating them. Can you please give your advice in terms of how many indexes should be used normally and how easy it is to update them?
View Replies !
Best Use Of Indexes
I have a situation where I am doing the following: Example keys: key1 key2 key3 Now "key1" is used a lot in WHERE queries with "key2" & "key3"; however they are not used all together at once.. "key1" is only used with 2 & 3 seperately. So I was wondering is it best to create 2 seperate indexes such as: key1 key2 key1 key3 ..or create one such as.. key1 key2 key3 ? I created the two seperate ones, but phpmyadmin is complaining about me having two indexes created for "key1".
View Replies !
Use Indexes?
My table has some indexes declared. How I can use them in the select queries in order to achieve better performance?
View Replies !
Preserving Indexes
I'm using phpMyAdmin for the most part. I notice that the index cardinality shows up as None in phpMyAdmin for each index I have. If I drop the index and re-create it, all of the indexes show their correct cardinality. I don't think phpMyAdmin is at fault because searching on the table before I fix it is sluggish until afterwards. Is the a command I could run that would re-index everything after I dump the data into the table? Or what is going on?
View Replies !
Two FULLTEXT Indexes
I'm building a new database and I will need a search engine for it. I wonder if it would be ok if the database contains two fulltext indexes.It's because my database will contain English document and French document.I would put two FULLTEXT indexes in my table so that way, you could do your research only on the French document or only on the English ones. So my question is, would it be better to put the two fulltext index in one table or do a table for the French articles and a table for the English articles.
View Replies !
More Than 32 Indexes With MyISAM?
I've searched Google every way I know how, and came up with two answers that refer to MAX_KEY and MI_MAX_KEY, along with a typedef for key_map. I have the 4.1.1 alpha source (4.0 is no good, because it doesn't support subqueries). I changed the two defines in sql/mysql_priv.h and include/myisam.h, respectively. The typedef for key_map is no longer ulong or ulonglong, but instead Bitmap(64); I left that alone. After compiling, an attempt to create a table with more than 32 indexes (which I absolutely must have) still shows an error referring to 32 max keys. What's going on here? I could not find anywhere in the code that generates that error which doesn't check either or both of the above defines. So why isn't it working? Is it hard coded somewhere?
View Replies !
MySQL Indexes
if the indexes of a table are dynamically updated... in other words, if I have a table updated every minute, do the related indexes are updated as well?
View Replies !
Enum Or Indexes
My question is, would there be a significant impact on optimization by removing the enum in favor of other tables.For example, in the table there is a column of type enum to represent the 50 states. Is there any advantage performance-wise to move these 50 states into a table?
View Replies !
Table Indexes
1. is this true that all the fields on which you will be doing search one should make them index? 2. is there a limit to how many index fiedls you can have? 3. i once was geting this error while creating a table "specified key can be max 500" when i got rid of index it got created sucessfully I don't know why?
View Replies !
Indexes, Primary Key
I have set up a temperature logging system with ds18s20 one-wire sensors. In the MySQL database I have a table with four columns - time as timestamp, outside, inside and server temperatures as floats. A small C program runs the Digitemp ( http://www.digitemp.com ) program every half hour from cron, parses the output and inserts now() and temperatures. The data is used by a web page, and I mostly select according to timestamp (for example, the last week).Would there be any performance to gain from creating an index on the timestamp? It is already ordered, ascending in the table. I have not set a primary key on the table either, would that be any advantage?
View Replies !
Define Indexes?
I'm wading through the waters of "MySQL/PHP Database Applications," and I still cannot get this INDEX malarcky into my head. What exactly is an index? What's a working example that would put it into clear understanding
View Replies !
Proper Indexes
I recently had an administrator on a system I built manually enter in grades twice for the same exam. I had made check to stop this when importing from a csv but did not think to check when manually entering grades. My bad. If I add an index for both Session_ID and SOMS_KEY would this fix the problem? I can't have the same SOMS_KEY which identifies a student written into the table for the same Session_ID. The Session_ID has all the exam grades for that session. Example: Session_ID, SOMS_KEY 61, 602 61, 602
View Replies !
FULLTEXT Indexes
I know that FULLTEXT indexes actually return meaningful results but I also suspect they add a lot of overhead to the database server.I can't change it for our existing application but for the next major revision I was planning to create a search table that contains all words that get entered into the database (apart from noise words) with an article ID.I think that might get a bit complicated though as it would have to return results and then scan through the text returned to highlight that word? Actually not that hard but is it worth it for performance benefits?
View Replies !
|
TRACKER
