diff --git a/db/nosql/column/clickhouse/clickhouse.txt b/db/nosql/column/clickhouse/clickhouse.txt
index 1b4f9a143..4f58e3528 100644
--- a/db/nosql/column/clickhouse/clickhouse.txt
+++ b/db/nosql/column/clickhouse/clickhouse.txt
@@ -22,10 +22,7 @@ https://clickhouse.com/docs/en/integrations/java/jdbc-driver
 compression
 https://habr.com/en/company/yandex/blog/457612/
 
-lsm
-https://habr.com/ru/companies/wildberries/articles/821865/
-
-internals
+internals, lsm
 https://habr.com/ru/companies/wildberries/articles/821865/
     system.parts
 
diff --git a/db/nosql/column/clickhouse/docs/tips.txt b/db/nosql/column/clickhouse/docs/tips.txt
new file mode 100644
index 000000000..243d1002d
--- /dev/null
+++ b/db/nosql/column/clickhouse/docs/tips.txt
@@ -0,0 +1,2 @@
+2023
+https://habr.com/ru/articles/743772/
diff --git a/db/nosql/column/clickhouse/feature/agg.txt b/db/nosql/column/clickhouse/feature/agg.txt
new file mode 100644
index 000000000..8e20607ed
--- /dev/null
+++ b/db/nosql/column/clickhouse/feature/agg.txt
@@ -0,0 +1,5 @@
+2024
+https://habr.com/ru/companies/oleg-bunin/articles/836078/
+    ! need to directly provide consistence of predaggr-table and src-one
+    !   ? using materialized-views (but m-v does not trigger updates/deletes)
+    ! projections - clickhouse makes automatically
diff --git a/db/nosql/column/clickhouse/feature/array.txt b/db/nosql/column/clickhouse/feature/array.txt
new file mode 100644
index 000000000..2a6822b41
--- /dev/null
+++ b/db/nosql/column/clickhouse/feature/array.txt
@@ -0,0 +1,4 @@
+2020
+https://altinity.com/blog/harnessing-the-power-of-clickhouse-arrays-part-1
+https://altinity.com/blog/harnessing-the-power-of-clickhouse-arrays-part-2
+https://altinity.com/blog/harnessing-the-power-of-clickhouse-arrays-part-3
diff --git a/db/nosql/column/clickhouse/feature/dictionary.txt b/db/nosql/column/clickhouse/feature/dictionary.txt
new file mode 100644
index 000000000..7b8b97023
--- /dev/null
+++ b/db/nosql/column/clickhouse/feature/dictionary.txt
@@ -0,0 +1,6 @@
+https://clickhouse.com/docs/en/sql-reference/dictionaries
+https://clickhouse.com/docs/en/sql-reference/functions/ext-dict-functions
+https://clickhouse.com/docs/en/sql-reference/functions/ym-dict-functions
+
+2024
+https://habr.com/ru/companies/oleg-bunin/articles/836078/
diff --git a/db/nosql/column/clickhouse/feature/engines.txt b/db/nosql/column/clickhouse/feature/engines.txt
index 6a47c90ea..e1fa6738d 100644
--- a/db/nosql/column/clickhouse/feature/engines.txt
+++ b/db/nosql/column/clickhouse/feature/engines.txt
@@ -1,4 +1,19 @@
 https://clickhouse.com/docs/ru/engines/table-engines
 https://clickhouse.com/docs/ru/engines/table-engines/mergetree-family
 https://clickhouse.com/docs/ru/engines/table-engines/mergetree-family/replacingmergetree
+    only eventually dedups (and on mutations)
 https://clickhouse.com/docs/en/engines/table-engines/special/join
+
+https://clickhouse.com/docs/en/guides/developer/deduplication
+https://kb.altinity.com/altinity-kb-schema-design/insert_deduplication/
+
+2024
+https://habr.com/ru/companies/oleg-bunin/articles/836078/
+    select ... final
+    optimize table <> final -- for replacingmergetree only
+    ! clickhouse has no transactionality !
+    index granularity (8192 - num of rows to read at once)
+    primary index is stored in RAM
+2021
+https://habr.com/ru/articles/539538/
+    ! need to read
diff --git a/db/nosql/column/clickhouse/feature/index.txt b/db/nosql/column/clickhouse/feature/index.txt
new file mode 100644
index 000000000..3092b9d30
--- /dev/null
+++ b/db/nosql/column/clickhouse/feature/index.txt
@@ -0,0 +1,4 @@
+https://clickhouse-docs.vercel.app/docs/en/optimize/sparse-primary-indexes
+    ! each part has its own primary index
+    sparse index - one 'mark' per group of rows 'granule'
+    it must fit into the RAM
diff --git a/db/nosql/column/clickhouse/feature/internals.txt b/db/nosql/column/clickhouse/feature/internals.txt
index 89e376e9b..a0a9261fe 100644
--- a/db/nosql/column/clickhouse/feature/internals.txt
+++ b/db/nosql/column/clickhouse/feature/internals.txt
@@ -13,6 +13,8 @@ https://clickhouse.com/docs/en/optimize/skipping-indexes
 
 2023
 https://clickhouse.com/blog/handling-updates-and-deletes-in-clickhouse
+https://habr.com/ru/companies/oleg-bunin/articles/726570/
+    ! perf-opt
 
 system db
 \c system
diff --git a/pl/java/libfws/spring/data/jdbc/docs/articles.txt b/pl/java/libfws/spring/data/jdbc/docs/articles.txt
index 995f4196d..c46161fac 100644
--- a/pl/java/libfws/spring/data/jdbc/docs/articles.txt
+++ b/pl/java/libfws/spring/data/jdbc/docs/articles.txt
@@ -1,5 +1,7 @@
-2022
 https://www.baeldung.com/java-jdbc
+https://www.baeldung.com/spring-data-jdbc-intro
+
+2022
 https://thorben-janssen.com/spring-data-jdbc-sequence/
     https://habr.com/ru/company/otus/blog/687386/
 https://thorben-janssen.com/spring-data-jdbc-custom-queries-and-projections/
diff --git a/pl/java/libfws/spring/data/jdbc/features/query-methods.txt b/pl/java/libfws/spring/data/jdbc/features/query-methods.txt
new file mode 100644
index 000000000..fe4322680
--- /dev/null
+++ b/pl/java/libfws/spring/data/jdbc/features/query-methods.txt
@@ -0,0 +1 @@
+https://docs.spring.io/spring-data/relational/reference/jdbc/query-methods.html