-- -- Testing memory usage of columnar tables. -- CREATE SCHEMA columnar_memory; SET search_path TO 'columnar_memory'; SET columnar.stripe_row_limit TO 50000; SET columnar.compression TO 'pglz'; CREATE TABLE t (a int, tag text, memusage bigint) USING columnar; -- measure memory before doing writes SELECT TopMemoryContext as top_pre, WriteStateContext write_pre FROM columnar_test_helpers.columnar_store_memory_stats() \gset BEGIN; SET LOCAL client_min_messages TO DEBUG1; -- measure memory just before flushing 1st stripe INSERT INTO t SELECT i, 'first batch', -- sample memusage instead of recording everyr row for speed CASE WHEN i % 100 = 0 THEN columnar_test_helpers.top_memory_context_usage() ELSE 0 END FROM generate_series(1, 49999) i; SELECT TopMemoryContext as top0, TopTransactionContext xact0, WriteStateContext write0 FROM columnar_test_helpers.columnar_store_memory_stats() \gset -- flush 1st stripe, and measure memory just before flushing 2nd stripe INSERT INTO t SELECT i, 'second batch', 0 /* no need to record memusage per row */ FROM generate_series(1, 50000) i; SELECT TopMemoryContext as top1, TopTransactionContext xact1, WriteStateContext write1 FROM columnar_test_helpers.columnar_store_memory_stats() \gset -- flush 2nd stripe, and measure memory just before flushing 3rd stripe INSERT INTO t SELECT i, 'third batch', 0 /* no need to record memusage per row */ FROM generate_series(1, 50000) i; SELECT TopMemoryContext as top2, TopTransactionContext xact2, WriteStateContext write2 FROM columnar_test_helpers.columnar_store_memory_stats() \gset -- insert a large batch INSERT INTO t SELECT i, 'large batch', -- sample memusage instead of recording everyr row for speed CASE WHEN i % 100 = 0 THEN columnar_test_helpers.top_memory_context_usage() ELSE 0 END FROM generate_series(1, 100000) i; COMMIT; -- measure memory after doing writes SELECT TopMemoryContext as top_post, WriteStateContext write_post FROM columnar_test_helpers.columnar_store_memory_stats() \gset \x SELECT (1.0 * :top2/:top1 BETWEEN 0.99 AND 1.01) AS top_growth_ok, (1.0 * :xact1/:xact0 BETWEEN 0.99 AND 1.01) AND (1.0 * :xact2/:xact0 BETWEEN 0.99 AND 1.01) AS xact_growth_ok, (1.0 * :write1/:write0 BETWEEN 0.99 AND 1.01) AND (1.0 * :write2/:write0 BETWEEN 0.99 AND 1.01) AS write_growth_ok, :write_pre = 0 AND :write_post = 0 AS write_clear_outside_xact; -- inserting another bunch of rows should not grow top memory context INSERT INTO t SELECT i, 'last batch', 0 /* no need to record memusage per row */ FROM generate_series(1, 50000) i; SELECT CASE WHEN 1.0 * TopMemoryContext / :top_post BETWEEN 0.98 AND 1.03 THEN 1 ELSE 1.0 * TopMemoryContext / :top_post END AS top_growth FROM columnar_test_helpers.columnar_store_memory_stats(); -- before this change, max mem usage while executing inserts was 28MB and -- with this change it's less than 9MB. SELECT (SELECT max(memusage) < 9 * 1024 * 1024 FROM t WHERE tag='large batch') AS large_batch_ok, (SELECT max(memusage) < 9 * 1024 * 1024 FROM t WHERE tag='first batch') AS first_batch_ok; \x SELECT count(*) FROM t; SET client_min_messages TO WARNING; DROP SCHEMA columnar_memory CASCADE;