Madison Kelly wrote:
Hi all,

Is there a fast(er) way to get the sum of all integer values for a certain condition over many thousands of rows? What I am currently doing is this (which takes ~5-10sec.):

OK, I'm assuming you've configured PG to your satisfaction and this is the only query giving you problems.

SELECT SUM (a.file_size) FROM file_info_1 a, file_set_1 b WHERE a.file_name=b.fs_name AND a.file_parent_dir=b.fs_parent_dir AND a.file_type=b.fs_type AND b.fs_backup='t';

You'll want to run EXPLAIN ANALYSE SELECT SUM... and post the output of that, although the query looks straightforward enough.

  Here are the schemas, in case they help:

tle-bu=> \d file_info_1                Table "public.file_info_1"
     Column      |  Type   |         Modifiers
 file_acc_time   | bigint  | not null
 file_group_name | text    | not null
 file_group_uid  | integer | not null
 file_mod_time   | bigint  | not null
 file_name       | text    | not null
 file_parent_dir | text    | not null
 file_perm       | text    | not null
 file_size       | bigint  | not null
 file_type       | text    | not null default 'f'::text
 file_user_name  | text    | not null
 file_user_uid   | integer | not null
    "file_info_1_display_idx" btree (file_parent_dir, file_name, file_type)
    "file_info_1_search_idx" btree (file_parent_dir, file_name, file_type)

tle-bu=> \d file_set_1               Table "public.file_set_1"
    Column     |  Type   |         Modifiers
 fs_backup     | boolean | not null default true
 fs_display    | boolean | not null default false
 fs_name       | text    | not null
 fs_parent_dir | text    | not null
 fs_restore    | boolean | not null default false
 fs_type       | text    | not null default 'f'::text
    "file_set_1_sync_idx" btree (fs_parent_dir, fs_name, fs_type)

2. Why do you have two identical indexes on file_info_1
4. Am I right in thinking that always, file_name==fs_name (i.e. they represent the same piece of information) and if so, why are you storing it twice? Same for _parent_dir too
5. file_type/fs_type are being held as unbounded text? Not an index into some lookup table or a varchar(N)?

Can you explain what you're trying to do here - it might be you want to alter your database design.
Richard Huxton
Archonet Ltd

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