On 09/09/16 14:50, Mark Kirkwood wrote:

Yeah, good suggestion about replacing (essentially) all the indexes with hash ones and testing. I did some short runs with this type of schema yesterday (actually to get a feel for if hash performance vs btree was compareable - does seem tp be) - but probably longer ones with higher concurrency (as high as I can manage on a single socket i7 anyway) is a good plan. If Ashutosh has access to seriously large numbers of cores then that is even better :-)



I managed to find a slightly bigger server (used our openstack cloud to run a 16 cpu vm). With the schema modified as follows:

bench=# \d pgbench_accounts
   Table "public.pgbench_accounts"
  Column  |     Type      | Modifiers
----------+---------------+-----------
 aid      | integer       | not null
 bid      | integer       |
 abalance | integer       |
 filler   | character(84) |
Indexes:
    "pgbench_accounts_pkey" hash (aid)

bench=# \d pgbench_branches
   Table "public.pgbench_branches"
  Column  |     Type      | Modifiers
----------+---------------+-----------
 bid      | integer       | not null
 bbalance | integer       |
 filler   | character(88) |
Indexes:
    "pgbench_branches_pkey" hash (bid)

bench=# \d pgbench_tellers
    Table "public.pgbench_tellers"
  Column  |     Type      | Modifiers
----------+---------------+-----------
 tid      | integer       | not null
 bid      | integer       |
 tbalance | integer       |
 filler   | character(84) |
Indexes:
    "pgbench_tellers_pkey" hash (tid)

bench=# \d pgbench_history
          Table "public.pgbench_history"
 Column |            Type             | Modifiers
--------+-----------------------------+-----------
 tid    | integer                     |
 bid    | integer                     |
 aid    | integer                     |
 delta  | integer                     |
 mtime  | timestamp without time zone |
 filler | character(22)               |
Indexes:
    "pgbench_history_pkey" hash (bid)

performed several 10 hour runs on size 100 database using 32 and 64 clients. For the last run I rebuilt with assertions enabled. No hangs or assertion failures.

regards

Mark


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