> On Thu, Mar 1, 2018 at 7:39 PM Amit Kapila <amit.kapil...@gmail.com> wrote:
I did some testing for performance of COPY command for zheap against heap, here are my results, Machine : cthulhu, (is a 8 node numa machine with 500GB of RAM) server non default settings: shared buffers 32GB, max_wal_size = 20GB, min_wal_size = 15GB Test tables and data: ---------------------------- I have used pgbench_accounts table of pgbench tool as data source with 3 different scale factors 100, 1000, 2000. Both heap and zheap table is lookalike of pgbench_accounts CREATE TABLE pgbench_zheap (LIKE pgbench_accounts) WITH (storage_engine='zheap'); CREATE TABLE pgbench_heap (LIKE pgbench_accounts) WITH (storage_engine='heap'); Test Commands: Command to generate datafile: COPY pgbench_accounts TO '/mnt/data-mag/ mithun.cy/zheapperfbin/bin/pgbench.data'; Command to load from datafile: COPY pgbench_heap FROM '/mnt/data-mag/ mithun.cy/zheapperfbin/bin/pgbench.data'; -- heap table COPY pgbench_zheap FROM '/mnt/data-mag/ mithun.cy/zheapperfbin/bin/pgbench.data'; -- zheap table Results ====== Scale factor : 100 ------------------------ zheap table size : 1028 MB heap table size: 1281 MB -- table size reduction: 19% size reduction. zheap wal size: 1007 MB heap wal size: 1024 MB -- wal size difference: 1.6% size reduction. zheap COPY execution time: 24869.451 ms heap COPY execution time: 25858.773 ms -- % of improvement -- 3.8% reduction in execution time for zheap Scale factor : 1000 ------------------------- zheap table size : 10 GB heap table size: 13 GB -- table size reduction: 23% size reduction. zheap wal size: 10071 MB heap wal size: 10243 MB -- wal size difference: 1.67% size reduction. zheap COPY execution time: 270790.235 ms heap COPY execution time: 280325.632 ms -- % of improvement -- 3.4% reduction in execution time for zheap Scale factor : 2000 ------------------------- zheap table size : 20GB heap table size: 25GB -- table size reduction: 20% size reduction. zheap wal size: 20142 MB heap wal size: 20499 MB -- wal size difference: 1.7% size reduction. zheap COPY execution time: 523702.904 ms heap COPY execution time: 537537.720 ms -- % of improvement -- 2.5 % reduction in execution time for zheap COPY command seems to have improved very slightly with zheap in both with size of wal and execution time. I also did some tests with insert statement where I could see some regression in zheap when compared to heap with respect to execution time. With further more investigation I will reply here. -- Thanks and Regards Mithun Chicklore Yogendra EnterpriseDB: http://www.enterprisedb.com