Databases
StackOverflow2013
Postsdbo
POSQL Query too slow even "Using Index" on EXPLAIN
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POSQL Query too slow even "Using Index" on EXPLAIN
    primarykey
    data
    text
    <p>i am trying to get all subscribers of a user</p> <p>my query:</p> <pre><code>SELECT COUNT(sub.id) as ids FROM subscribers as sub WHERE suid=541839243781 </code></pre> <p>EXPLAIN prints:</p> <pre> ╔════╦═════════════╦═══════╦══════╦═══════════════╦═════╦═════════╦═══════╦═══════╦═════════════╗ ║ id ║ select_type ║ table ║ type ║ possible_keys ║ key ║ key_len ║ ref ║ rows ║ Extra ║ ╠════╬═════════════╬═══════╬══════╬═══════════════╬═════╬═════════╬═══════╬═══════╬═════════════╣ ║ 1 ║ SIMPLE ║ sub ║ ref ║ i3 ║ i3 ║ 8 ║ const ║ 47890 ║ Using index ║ ╚════╩═════════════╩═══════╩══════╩═══════════════╩═════╩═════════╩═══════╩═══════╩═════════════╝ </pre> <p>so at the moment the total count i get is around <code>48k</code> and it takes <code>0.0333</code> to load... what if this goes up to <code>1m</code> or <code>5m</code> ?? then it could take ages to load up...</p> <p>my indexes on subscribers table are:</p> <pre> ╔═════════════╦════════════╦═══════════════════╦══════════════╦═════════════╦═══════════╦═════════════╦══════════╦════════╦══════╦════════════╦═════════╗ ║ Table ║ Non_unique ║ Key_name ║ Seq_in_index ║ Column_name ║ Collation ║ Cardinality ║ Sub_part ║ Packed ║ Null ║ Index_type ║ Comment ║ ╠═════════════╬════════════╬═══════════════════╬══════════════╬═════════════╬═══════════╬═════════════╬══════════╬════════╬══════╬════════════╬═════════╣ ║ subscribers ║ 0 ║ PRIMARY ║ 1 ║ id ║ A ║ 60251 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ║ subscribers ║ 1 ║ total_subscribers ║ 1 ║ id ║ A ║ 60251 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ║ subscribers ║ 1 ║ total_subscribers ║ 2 ║ suid ║ A ║ 60251 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ║ subscribers ║ 1 ║ i3 ║ 1 ║ suid ║ A ║ 6025 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ║ subscribers ║ 1 ║ i3 ║ 2 ║ uid ║ A ║ 60251 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ║ subscribers ║ 1 ║ i3 ║ 3 ║ id ║ A ║ 60251 ║ NULL ║ NULL ║ ║ BTREE ║ ║ ╚═════════════╩════════════╩═══════════════════╩══════════════╩═════════════╩═══════════╩═════════════╩══════════╩════════╩══════╩════════════╩═════════╝ </pre> <p>so how can i make this query more efficient?</p>
    singulars
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PTQuestion
    1. USVadim Ponomarev
    1. USfxuser
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    3. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POSQL Query too slow even "Using Index" on EXPLAIN
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    2. VO
      singulars
      1. POSQL Query too slow even "Using Index" on EXPLAIN
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    3. VO
      singulars
      1. POSQL Query too slow even "Using Index" on EXPLAIN
      1. This table or related slice is empty.
      1. VTApproveEditSuggestion
    1. COIf I'm reading data correctly you don't have dedicated index for "suid" column. Is "suid" column values unique globally or only for each subscriber?
      singulars
      1. POSQL Query too slow even "Using Index" on EXPLAIN
      1. USVadim Ponomarev
    2. COedited indexes, forgot one index
      singulars
      1. POSQL Query too slow even "Using Index" on EXPLAIN
      1. USfxuser
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload