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e9baa5e9fa
Haribabu Kommi, reviewed by Dilip Kumar and Rafia Sabih. Various cosmetic changes by me to explain why this appears to be safe but allowing inserts in parallel mode in general wouldn't be. Also, I removed the REFRESH MATERIALIZED VIEW case from Haribabu's patch, since I'm not convinced that case is OK, and hacked on the documentation somewhat. Discussion: http://postgr.es/m/CAJrrPGdo5bak6qnPWe8Kpi8g_jfQEs-G4SYmG9y+OFaw2-dPvA@mail.gmail.com
43 lines
1.4 KiB
SQL
43 lines
1.4 KiB
SQL
--
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-- PARALLEL
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--
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-- Serializable isolation would disable parallel query, so explicitly use an
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-- arbitrary other level.
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begin isolation level repeatable read;
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-- encourage use of parallel plans
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set parallel_setup_cost=0;
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set parallel_tuple_cost=0;
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set min_parallel_table_scan_size=0;
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set max_parallel_workers_per_gather=4;
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--
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-- Test write operations that has an underlying query that is eligble
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-- for parallel plans
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--
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explain (costs off) create table parallel_write as
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select length(stringu1) from tenk1 group by length(stringu1);
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create table parallel_write as
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select length(stringu1) from tenk1 group by length(stringu1);
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drop table parallel_write;
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explain (costs off) select length(stringu1) into parallel_write
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from tenk1 group by length(stringu1);
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select length(stringu1) into parallel_write
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from tenk1 group by length(stringu1);
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drop table parallel_write;
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explain (costs off) create materialized view parallel_mat_view as
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select length(stringu1) from tenk1 group by length(stringu1);
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create materialized view parallel_mat_view as
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select length(stringu1) from tenk1 group by length(stringu1);
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drop materialized view parallel_mat_view;
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prepare prep_stmt as select length(stringu1) from tenk1 group by length(stringu1);
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explain (costs off) create table parallel_write as execute prep_stmt;
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create table parallel_write as execute prep_stmt;
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drop table parallel_write;
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rollback;
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