From fec0f8e103c170999e90e55ff351229cbbf4116f Mon Sep 17 00:00:00 2001 From: mnoskov Date: Sun, 15 Mar 2026 17:23:18 +0300 Subject: [PATCH] =?UTF-8?q?=D0=B8=D1=81=D0=BF=D1=80=D0=B0=D0=B2=D0=B8?= =?UTF-8?q?=D0=BB=20=D0=BF=D1=80=D0=B0=D0=BA=D1=82=D0=B8=D0=BA=D1=83=20'EX?= =?UTF-8?q?PLAIN=20=D0=B8=20EXPLAIN=20ANALYZE'?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- .../4. EXPLAIN и EXPLAIN ANALYZE/DQL_explain_analyze_practice.sql | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mnoskov/postgresql/9. Оптимизация/4. EXPLAIN и EXPLAIN ANALYZE/DQL_explain_analyze_practice.sql b/mnoskov/postgresql/9. Оптимизация/4. EXPLAIN и EXPLAIN ANALYZE/DQL_explain_analyze_practice.sql index 9db5b58..d3c362e 100644 --- a/mnoskov/postgresql/9. Оптимизация/4. EXPLAIN и EXPLAIN ANALYZE/DQL_explain_analyze_practice.sql +++ b/mnoskov/postgresql/9. Оптимизация/4. EXPLAIN и EXPLAIN ANALYZE/DQL_explain_analyze_practice.sql @@ -124,8 +124,8 @@ JOIN orders o ON u.id = o.user_id JOIN order_items oi ON o.id = oi.order_id JOIN products p ON oi.product_id = p.id WHERE u.country = 'RU' AND p.category = 'Электроника'; --- Порядок чтения таблиц: order_items -> products -> orders -> users --- Количество строк: order_items - 12, products - 3, orders - 1, users - 0 +-- Порядок чтения таблиц: products -> order_items -> orders -> users +-- Количество строк: products - 3, order_items - 12, orders - 1, users - 0 -- Если у country и category будут индексы, то запрос ьудет выполняться побыстре, потому что будет Index Scan, а не Seq Scan