Mysql – SQL indexing with 2 join tables
I have 3 tables. country, team, player table Country id name 1 x 2 x 3 x table Team id name country_id 1 x 1 2 x 1 3 x 1 table Player id name country_id team_id 1 x 1…
Rails 7 + PostgreSQL: Super slow searching data in a table having 1,2M rows. How do I speed it up?
I have a database table that having close to 100 columns - 25 columns are STRING, the rest is INT/DECIMAL/BOOL. This is the query that I am trying to run - the query is generated based on the search criteria…
mysql5.7 order by id desc limit n ;Optimizer selects primary key index
CREATE TABLE `test` ( `id` bigint UNSIGNED NOT NULL AUTO_INCREMENT, `month` timestamp NOT NULL DEFAULT '2018-01-01 00:00:00', `b` varchar(255) NOT NULL DEFAULT '', `c` varchar(255) NOT NULL DEFAULT '', `d` varchar(255) NOT NULL DEFAULT '', `e` varchar(255) NOT NULL DEFAULT…
Mysql – SQL Inner join with where clause works fast with one condition, but not when activeFlag is added
I have a query like select C.customerId, C.firstName, C.LastName, R.IsActive from Customer as C Inner join Rider as R ON R.customerId = C.customerid where R.rideid = 'xyz' and R.rideareacode = 'abc' and R.isActive = 1 This is taking too much…
How to Optimize Search Queries on a Large PostgreSQL Table without Compound Indexes?
I have a PostgreSQL table named users which contains between 20 to 30 million records. The table has the following columns: id, tenant_id, name, company, location, and description. I need to perform generic search queries on this table with various…
Seo – Angular, How lazy loaded components get crawled and indexed by google bot
we load angular component on scroll for better page performance but these component content not crawled by google bot. we have implemented angular ssr & prerendering. we are using scroll event @HostListener('window:scroll', ['$event'])
Postgresql – Efficiently indexing sparse nullable column in Postgres
I need to index a Postgres column that consists of mostly NULL values. I don't want the NULL values to be stored in the index (to make the index smaller, and to speed up row insertion). However, adding a partial…
MongoDB two indexes with different directions
I have one index created { v: 2, key: { xxxx: 1 }, name: 'xxxx', background: true }, But I have a lot of long queries with "sort": { "xxx": -1 }, Will creating an additional index with -1 help…
Javascript – Matrix indexing/flattening
I am given a matrix with dimensions dim = nxmx4. I would like to flatten this matrix to a new 1-dimensional matrix with length l = n*m*4 using 3 nested for-loops. for (let x = 0; x < n; x++)…
Postgresql – Postgres not using index when filtered/indexed value does not exist
In Postgres 16.2 I've a table Product with extra index: CREATE TABLE Product (id SERIAL , name: text, companyId: number, PRIMARY KEY (id)); CREATE INDEX product_company_id ON Product (companyId); The table has about 12M rows. When I search for a…