A database structure that can improve the speed of queries at the cost of disk space and slower inserts/updates. It stores a copy of one or more columns but structures the data differently to allow for faster access.

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MYSQL Indexes when looking up on alternating sets of columns

I have a table that looks like: CREATE TABLE `connections` ( `connection_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT, `service_id` smallint(5) unsigned DEFAULT NULL, `parent_id` bigint(20) ...
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3answers
268 views

Mysql - How to Optimize Retrieval Time in a Table

I have query like this! which has 200 million Records in a single table.. I am using BTree Indexes in my table... mysql> select COUNT(DISTINCT id) from [tablename] where [columname] >=3; ...
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2answers
212 views

Minimizing Indexed Reads with Complex Criteria

I'm optimizing a Firebird 2.5 database of work tickets. They're stored in a table declared as such: CREATE TABLE TICKETS ( TICKET_ID id PRIMARY KEY, JOB_ID id, ACTION_ID id, STATUS str256 ...
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2answers
64 views

best possible index on this situation

create table #testing(id int, name varchar(50)) go Insert Into #testing Values(231, 'fasd') Insert Into #testing Values(232, 'dsffd') Insert Into #testing Values(233, 'xas') Insert Into #testing ...
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2answers
142 views

mysql need help optimizing query

I have a table containing servers logs, and another table containing rules to match certain and drop them. The logs tables contains around 1 million rows, and there are about 20-30 rules. The ...
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1answer
205 views

Why would the size of MySQL MyISAM table indexes (aka MYI file) not match after mysqldump import?

I've been archiving some MySQL (version 5.0.96) MyISAM tables locally and deleting from my server after checking the data. Every time the process has been pretty similar and comes off mostly without a ...
2
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1answer
2k views

MySQL requires FORCE INDEX on huge table and simple SELECTs

We have an application which stores articles from different sources in a MySQL table and allows users to retrieve those articles ordered by date. Articles are always filtered by source, so for client ...
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1answer
36 views

Sybase ASA: Saving and dropping all foreign keys and most Primary Keys for (Bulk) Insert

Background Information: I am trying to migrate from an ASA 12 Database, to a ASA 12 Database by using a Remote Server. I have to migrate a lot of Rows (not all), spread over a lot of tables (not ...
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1answer
84 views

Best Indexing Strategy for Query with Equality[A], Range[B], Group By[C], AND Order By[count(P)]

I have a poorly performing query: SELECT user_id, count(item_id) as count FROM table items WHERE category = 'magazine' AND created_at > 1384754400 GROUP BY user_id ORDER BY count(item_id) desc ...
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1answer
152 views

How to repair all indexes in a MySQL database?

My database got corrupted, and now the php app is throwing this error: Invalid query: Can't find FULLTEXT index matching the column list The error is not very useful, since it doesn't say what ...
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1answer
276 views

optimizing MySQL for traffic analytics system

background : I've developed a URL shortener system like Bitly with same features , so the system also tracks clickers info and represent as graphs to the person who has shorten the link as ...
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1answer
586 views

Slow insert with MySQL full-text index

I use a full-text index in a MySQL table, and each insert into this table takes about 3 seconds. It seems that MySQL rebuilds (a part) of the full text index after each insert/update. Is this right? ...
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1answer
64 views

MySQL - Indexes deleted, reduced column size but table size increases

Here is the original table definition which contains 107547934 (~107.5M) rows CREATE TABLE `twitter_tweets` ( `id_str` varchar(100) CHARACTER SET utf8 COLLATE utf8_unicode_ci NOT NULL ...
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1answer
56 views

Tablespace of an index organized table

I want to find the tablespace of an index organized table with primary key. With dba_segments I can only find the tablespace for the primary key. But how can I find the tablespace for the table?
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1answer
143 views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
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1answer
43 views

MySQL is using wrong index

This is my table: - user_id INT (foreign key on `user` with the reference `id`) - question_id INT (foreign key on `question` with the reference `id`) - option_id INT (foreign key on `option` with the ...
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1answer
104 views

Is searching an alternate index on a partitioned myISAM table concurrent or serial?

I have a myISAM table with 30 partitions. The primary key is a SHA1 hash value, which is also used in the partition selection function. I also have an alternate key - an autoincrement integer. Since ...
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1answer
41 views

When to use hashtable over binary search tree vice verse for Database Index

Database Index can be constructed using binary search trees (BST) or HashTables , From my understanding so far , HashTables are superior to BST in terms of time taken for searching and insertions ...
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1answer
126 views

Should I index before or after importing a dump?

I am using mongodb to persist a very big-size (90G), which has nearly 40,000,000 items. I read and parse this file and insert all items into mongodb (my programming language is perl, batch_insert, and ...
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1answer
52 views

Optimizing a union query

SELECT id FROM user WHERE id IN ( 2,3,4,7,9,21,23,45,324,12,43,254 ) UNION SELECT DISTINCT user_id FROM workgroup_users WHERE workgroup_id IN ( 1,345,34,654,213,123,5,2,3,4 ) I know we should not ...
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0answers
193 views

Using an enum as part of an index definition

When I use an ENUM column in a table the ORDER BY uses the ordinal of the ENUM not its value. I wasn't aware of that. So my question is what are the subtle issues when an ENUM is part of an index ...
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0answers
306 views

MySql INNER JOIN doesn't use composite index

I have two tables, table A which contains date and name of table B entry and table B which contains its name and type. Table a has a composite index on table_b_name and date. I'm selecting all table A ...
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0answers
60 views

Error creating spatial index sqlserver

I am creating spatial index on sqlserver table. CREATE SPATIAL INDEX [SIndex_udt_cell_SP_GEOMETRY] ON [udt_cell] ( [SP_GEOMETRY] )USING GEOMETRY_GRID WITH ( BOUNDING_BOX =(80.0713, 26.389581, ...
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0answers
311 views

Is it possible to optimize a range query so an explain statement would state “using index” instead of “using index condition”?

I have a very large table where specific queries made by my application are timing out. The table looks something like this: LargeTable ------------ Id [BIGINT(20)] UtcTimestamp [BIGINT(20)] Pivot ...
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0answers
58 views

How to/advice for hosting a multi-user database on the cloud with specific objectives

I have developed an application that users will be able to download and create an account with through our company. This application will always be connected to the internet. I have been testing the ...
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0answers
113 views

How implement MySQL unique index with two foreign key that one can be null?

I would know if can be declared in MySQl to create an index constraints in a table with two foreign key that one can be null. For example cannot be repeated a null foreign key with the other foreign ...