I
have performance issues with two big tables. Those tables are located
on an oracle remote database. I'm running the quert : insert
into local_postgresql_table select * from oracle_remote_table.
The
first table has 45M records and its size is 23G. The import of the data
from the oracle remote database is taking 1 hour and 38 minutes. After
that I create 13 regular indexes on the table and it takes 10 minutes
per table ->2 hours and 10 minutes in total.
The
second table has 29M records and its size is 26G. The import of the
data from the oracle remote database is taking 2 hours and 30 minutes.
The creation of the indexes takes 1 hours and 30 minutes (some are
indexes on one column and the creation takes 5 min and some are indexes
on multiples column and it takes 11 min.
Those
operation are very problematic for me and I'm searching for a solution
to improve the performance. The parameters I assigned :
min_parallel_relation_size = 200MB
max_parallel_workers_per_gather = 5
max_worker_processes = 8
effective_cache_size = 2500MB
work_mem = 16MB
maintenance_work_mem = 1500MB
shared_buffers = 2000MB
RAM : 5G
CPU CORES : 8
-I
tried running select count(*) from table in oracle and in postgresql
the running time is almost equal.
-Before
importing the data I drop the indexes and the constraints.
-I
tried to copy a 23G file from the oracle server to the postgresql
server and it took me 12 minutes.
Please
advice how can I continue ? How can I improve something in this
operation ?
