Use this tag for questions about improving the performance and/or efficiency of database queries.

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2
votes
1answer
33 views

How to optimize this query on Postgres

I'm trying to make a relatively simple query, but it's taking much longer than I'd expect. I have an index in place, but it doesn't seem to be helping much. Here's the query. It sometimes takes up to ...
3
votes
1answer
181 views

Mysql join table order by index

First Master Table CREATE TABLE `edipostingmaster` ( `ID` bigint(20) NOT NULL AUTO_INCREMENT, `applied` int(11) DEFAULT '0', `fileName` varchar(255) DEFAULT NULL, `checkNo` varchar(100) ...
0
votes
0answers
32 views

How to concatenate using cast(collect()) in Oracle DB?

My current query: select distinct mb.BP_TYPE,mb.ABS,mb.BLD_SEQ_CODE, mb.BPCODE||'~'||(select LISTAGG(mbp.PROCEDURE,' ') within group(order by mbp.LINE,mbp.SLN1,mbp.SLN2) from MIS_BS_BB_PROC mbp ...
1
vote
1answer
118 views

Mysql Partitions with Partition limit

I have a partition table on basis of Primary key having 1.5 Billion rows in it. But when i check ibd files only 80 ibd show in GB's whereas 120ibd shows 1MB file. I would like to know how does the ...
0
votes
0answers
22 views

In which order does a mongodump --query executes

In which order does a mongodump --query executes, is from last insert to first insert or the other way around, if it is other way around is there any option that I can pass to mongodump --query, so ...
4
votes
2answers
130 views

slow select query on datetime column

I have a table in MySQL which has approximately 10 million records, and now a query which used to take micro seconds now takes more that 8 seconds to execute! Here is my table structure: CREATE TABLE ...
5
votes
3answers
2k views

Some book suggestions for performance tuning

I am in the process of improving performance on our database application. While I am not a DBA, I am pretty comfortable with SQL. I am after a book that can help me understand how queries written in ...
1
vote
1answer
88 views

Auto update stats turned off for a user database on SQL Server

While trying to improve the performance of few queries, we found via execution plan that there were lot of index / clustered index seeks. Therefore: First thing we did, was to check our Re-indexing ...
0
votes
1answer
29 views

New column to a base table

I want to add a new column to a base table, and add that new column to an existing view... So all selects/updates/deletes translate back to the original table How can I do that? Thanks ...
3
votes
1answer
48 views

Query Plan Error

I have an interesting situation. I use SQL2014 Enterprise version with SP1. The following query results an error message : The query processor ran out of internal resources and could not produce ...
6
votes
2answers
202 views

Effect of an index on update statements where update column is not in an index

I constantly see people say that indexes slow down update, delete and insert. This is used as a blanket statement, as if it is an absolute. While tuning my database to improve performance, I keep ...
3
votes
2answers
60 views

SQL Server “fix” query for Hash Match instead of Nested Loops

At the moment I have a view that is running very slow. It takes about 3 minutes to execute. This suddenly happened. To debug what was going on I used an old dataset and compared both queries. On the ...
1
vote
2answers
4k views

Optimize IN clause in where query with order by - MySQL

I am trying to optimize a query that using IN clause in WHERE to avoid file sorting. To make it easy , I created the following sample which shows the problem. Here is my query: SELECT * FROM `test` ...
-3
votes
0answers
39 views

Procedure taking so much time [closed]

Can anyone help me out. This is first time im working on performance tuning can anyone help me out. If want i can paste the proc also.
1
vote
0answers
42 views

Oracle, Cursor_Sharing = Force and Queries with literal comparisons forcing FTS

I have the following scenario: Oracle 11.2.0.3 A 3rd party application, that requires cursor_sharing = TRUE A table (T2310) with a indexed field (C1000000161) that has no duplicated values Result ...
-1
votes
2answers
56 views

SQL query execution differs each and every time in SSMS

I have used below query to fetch maximum of 6000 records in SQL Server 2012. Select A.Date, A.City From dbo.TBL_Auction (NoLock) A Inner Join dbo.TBL_PLACE (NoLock) B On A.Place_Fk_Id = B.Place_Pk_Id ...
3
votes
2answers
56 views

What's the best way to diagram this “relation” looking for performance and|or disk space savings

I am working in a DB diagram and I have a table called cm_identifier_type. Each record of this table can have or not a downloadable file (saved a file path). I have identified two possibles ways to ...
2
votes
2answers
46 views

Search multiple values in multiple columns

I have a table results with this fields: id results_id number_one (int) number_two (int) number_three (int) number_four (int) number_five (int) Each number_* column can contain a number from 01 to ...
3
votes
1answer
158 views

Do WHERE IN queries reindex the table after each set within the query?

I have a basic WHERE IN query that takes too long (30+ secs) to process. DELETE FROM `table1` WHERE ( djID, localID ) IN (("128","26"),("110","32")) The table I'm querying on has about 20 million ...
4
votes
2answers
60 views

Update fields that contains certain prefix by lookup table

I have a temporary table #NAMEOLD_NAMENEW which contains a column NAMEOLD and a column NAMENEW where every row contains the old and new value of a value to be updated. This table consists of roughly ...
1
vote
1answer
69 views

Decrease Query Execution Time

I have been having issues with 2 queries with query execution times up to 250 seconds for each query. The tables joined have each less than 10,000 rows, with exception to 2 tables that have around 60k ...
2
votes
1answer
37 views

Key/Value table with limiters

I'm sure someone must have hit this or a problem like this before but I'm not finding anything on a google or DBA exchange search. I have a table storing key/value pairs. There are also 2 limiting ...
0
votes
2answers
60 views

Perform join on multiple tables

I have three tables right now in a postgres DB: Artists ID Name Shows ID Date Venue Price Is_sold Ages Time Multi_day Pit Artists_shows ID Show_id ...
3
votes
1answer
53 views

Indices for a join query with datetime range

Given the following query: SELECT DISTINCT COUNT(DISTINCT "patients"."id") FROM "patients" INNER JOIN "transactions" ON "transactions"."patient_data_id" = "patients"."patient_data_id" WHERE ...
4
votes
1answer
62 views

UPDATE on column referenced in sub-query

We have a query that updates a column for all rows matching a condition which involves a subselect on said column, like the following: update CE_WORKSET_READ_ENTRY workset set workSet.MARK = 0, ...
1
vote
1answer
78 views

SELECT Causes Performance Issue [closed]

I have a SQL SELECT statement that has joins on 27 of our warehouse tables. Original statement was taking more than an hour everyday so I decided to optimize it. I created some indexes but still it ...
7
votes
1answer
87 views

Improving a DbGeography query

I am still new to database administration and I'm trying to optimise a search query. I had a query which looked like this and took 5-15 seconds to execute in some cases, and also was causing 100% CPU ...
3
votes
1answer
61 views

Update multiple Ids when SET = (Sql Query)

I want to update multiple records however the value being set is based on the primary key of the given record. This is not an issue with a single record as I can use: UPDATE T1 SET A1 = (SELECT ...
1
vote
0answers
70 views

High load on server because of one query

I have one query running from last stable version of wordpress on causing high load on my centos 6.7 server I enabled slow query log thought /etc/my.cnf file to record which sql cause this problem ...
2
votes
0answers
37 views

Composite index works for larger set of data, but not smaller

This is a follow on question to optimise my.ini for key query Data model: DROP TABLE IF EXISTS `contract`; CREATE TABLE IF NOT EXISTS `contract` ( `id` int(11) NOT NULL AUTO_INCREMENT, ...
2
votes
1answer
94 views

Can I set order of query execution?

Below query is executing in approx 5 min: SELECT COUNT(distinct B.CALL_ID), C.IVR_APPLN_NAME FROM PTDT.TDT_CALL_DATA AS A, PTDT.TDT_IVR_CALL_APPLICATIONS AS B, ...
7
votes
1answer
142 views

Lead/Lag Implementation in SQL Server 2008 R2: Max memory exceeded

Background I'm trying to establish a "visits" sequence, wherein if an animal is detected at essentially the same place (General_Location) it counts as a single visit, but if it goes elsewhere and ...
4
votes
2answers
72 views

Indexed but still slow during query

I have a table that stores REST requests and responses: CREATE TABLE ws_call_logs ( id BIGINT NOT NULL, ws_method_id BIGINT NOT NULL, device_id ...
18
votes
2answers
348 views

Huge data and performance in SQL Server

I've written an application with a SQL Server backend that collects and stores and extremely large amount of records. I've calculated that, at the peak, the average amount of records is somewhere in ...
1
vote
1answer
26 views

Struggling to design addresses table for fast querying

I have two tables: addresses and locations. Locations zipcode city county state Addresses line1 line2 city county state zipcode Posts Id Address_id Body All my users are required to provide at ...
1
vote
1answer
25 views

What are the consequences of enabling slow_query_log and flushing the cache on mysql?

I have a large database that is performing poorly recently. I want to enable the slow_query_log to investigate the queries and flushing the cache but I need to know what are the consequences of doing ...
4
votes
2answers
775 views

MySQL queries are 10 to 100 times slower after OS reboot

I have a MySQL server running on Ubuntu. If I restart the MySQL, everything is fine. If I however restart the OS, my queries take anywhere from 10 times to 100 times as long. The only "solution" to ...
2
votes
1answer
100 views

MDX query is SLOWER with warm cache

I have a MDX query that executes faster on cold cache than warm cache. If I ran the same MDX query after restarting SSAS it takes 14 seconds. All subsequent runs of the same statement then take 50 ...
0
votes
2answers
58 views

How to improve performance of frequently updated table in mysql?

my table structure:: CREATE TABLE `gps_device_data`( `imei_no` bigint(15) NOT NULL DEFAULT '0', `ioelementpriority` int(1) DEFAULT NULL, `longitude` int(15) DEFAULT NULL, `latitude` int(15) ...
2
votes
2answers
66 views

Optimizing a MySQL “IN” query

I'm trying to optimize a MySQL table for a query of the form: SELECT Col1, Col2 FROM MyTable WHERE Col3 IN('Val1','Val2','Val3',...) I've added an index to the table: ALTER MyTable ADD ...
0
votes
1answer
25 views

Track database name in anemometer queries

Hello i have installed anemometer on our server in order to see the queries that need optimization. From the website hosted a few have a wordpress blog on them so it is hard to guess witch one is ...
19
votes
2answers
25k views

Increasing work_mem and shared_buffers on Postgres 9.2 significantly slows down queries

I have a PostgreSQL 9.2 instance running on RHEL 6.3, 8-core machine with 16GB of RAM. The server is dedicated to this database. Given that the default postgresql.conf is quite conservative regarding ...
0
votes
1answer
58 views

9 Minute Long Running Query [closed]

We recently stood up Documentum. We have a query that runs 9 minutes. We have applied indexes, this is a cotts product, the query runs against a view that the product creates. Below is the syntax: ...
3
votes
1answer
166 views

Minimizing Page Fetches

I have a complicated database structure and am trying to use it to retrieve Records based on multiple selection criteria from several tables. As a general rule, is it better to attempt to use ...
0
votes
0answers
20 views

Is there something like Query Analyzer for Postgres?

We are running EF6 and I'm trying to find out exactly what query is running against our Postgres database. With Sql Server, I would just fire up Query Analyzer and look at the query there. Is ...
0
votes
1answer
42 views

Very slow query, not sure if MySQL index is being used

I have a query which includes a join and I have an index on the tables: SELECT e.entry, e.user_id from entries e left join users u on e.user_id=u.user_id where e.tenant_id=? AND u.active=1 AND ...
0
votes
1answer
58 views

Optimizing slow query

For a few days now, i'm trying to optimize this query. But still I haven't found the right solution in how to fix this. The contents table contains about 20 million records. As the connect table ...
0
votes
1answer
29 views

Can I use the cost of a query to prove its efficiency when there is only a small number of rows?

Can I run EXPLAIN (Oracle) for a query when there is only a few dozen rows in the table and use the cost to prove whether the query is efficient or not ? Can you measure the efficiency of a query ...
3
votes
3answers
448 views

selecting multiple instances of a record based on record lifespan over years

I have a table of items that have a origin date and a life span. I want to create a procedure that selects all of the items that will need to be replaced in a specific duration. I feel like there is a ...
1
vote
0answers
33 views

Query slow on subscriber but fast on publisher (Merge Replication)

As the title suggests, I am having issues with performance with my subscriber. I run the exact same query (it's a recursive query with a few joins but nothing too serious). I can run this query on my ...