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185 строки
8.9 KiB
Plaintext
185 строки
8.9 KiB
Plaintext
2023
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PostgresProfessional - DBA2 Administration of 18 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6L72nIqJ-l-pscc6WxtW4G1
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PostgresProfessional - RogovLuzanovTolmachyov - QPT13 - Query Optimization of p12
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https://postgrespro.ru/education/courses/QPT
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6JW80WBHPOe-SMJD2NOjmge
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p11 - Optimization Tricks of 1:06:08
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https://www.youtube.com/watch?v=AsaGNjJtrR4
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! 6:00 vacuum cfg
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! autovacuum_max_workers, autovacuum_analyze_scale_factor
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! 11:00 io cfg
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! seq_page_cost = 1.0
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! random_page_cost = 4.0 # for ssd recommended to set 1.1
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! effective_io_concurrency = 1
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! 12:00 cpu cfg
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! cpu_tuple_cost = 0.01
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! cpu_index_tuple_cost = 0.005
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! cpu_operator_cost = 0.0025
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! CREATE FUNCTION ... COST <cost> # 1 for c-function, 100 - for user-defined
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! 14:00 parallel cfg
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! parallel_setup_cost = 1000
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! parallel_tuple_cost = 0.1
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! ...
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! cursor_tuple_fraction = 0.1
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! 18:00 ram settings
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! work_mem = 4MB # pretty low, need to increase
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! hash_mem_multiplier = 1
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! maintanance_work_mem = 64MB
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! effective_cache_size = 4GB
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! 20:00 some cfg can be set at tablespace/db/role/routine/session/transaction level
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! ALTER TABLESPACE SET ...
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! ALTER DATABASE SET ...
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! ALTER ROLE [IN DATABASE ...] SET ...
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! ALTER ROUTINE SET ...
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! SET [LOCAL] ...
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! 24:00 debug cfg
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! enable_seqscan
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! enable_indexscan, enable_bitmapscan, enable_indexonlyscan
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! enable_nestloop, enable_hashjoin, enable_mergejoin
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! enable_hashagg, enable_sort, enable_incremental_sort
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! force_parallel_mode
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! 39:00 manual join order control
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! join_collapse_limit # 1 - for manual
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! from_collapse_limit
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! !!! move parts of query to CTE (in order to reduce number of joins and make planner work easier)
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! 42:00 ... with b as materialized (....)
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! first calc CTE (marked with b at plan) - not effective, but good for debug/trace purposes
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p10 - profiling of 37:49
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https://www.youtube.com/watch?v=o5T0ApVFcDc
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! 16:00 log_min_duration_statements=0 # time and text of all queries
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! log_line_prefix # identity info
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! # analyse via pgBadger tool
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! 19:00 pg_stat_statements ext
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! 22:00 set pg_stat_statements.track = 'all'; # store all queries info, including compound ones
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!
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p9 - Statistics of 46:28
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https://www.youtube.com/watch?v=I4cedjshRrs
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! pg_class - num of tuples/pages (reltuples/relpages) for tables
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! setting default_statistics_target = 100
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! "selection size" for table analysis
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! pg_stats - n_distinct, null_tract - ration of uniq vals
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! most_common_vals, most_common_freqs
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! pg_statistics_ext, pg_statistics_ext_data, pg_stats_ext view (for dependent column values)
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p8 - Merge Join of 24:26
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https://www.youtube.com/watch?v=urerHBMGc14
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! set should be sorted first (either from downstream node of plan or from idx)
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! Merge Join: ...
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! Merge Cond: ...
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! 18:00 Sort:
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! Sort Key:
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! Sort Method:
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! Buffers: ...
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! 20:00 Agg...
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! Gather Merge:...
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p7 - Hash Join of 29:03
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https://www.youtube.com/watch?v=zH_LJAsYvcU
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! can be in a single (Batches: 1) or double-batches (when can't feet into RAM)
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! 3:00 work_mem * hash_mem_multiplier
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! 5:00 Hash Join
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! Hash Cond: (... = ...)
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! -> Seq Scan on <tbl> alias
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! -> Hash
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! -> Seq Scan on ...
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! Hash Full Join
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! 7:00 hash joing can be used for DISTINCT
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! Hash Aggregate ...
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! Group Key ...
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! explain (analyze, settings - to show all non-std param-values, ... )
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!
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! hash-table need to be build my lower set of rows (to decrease RAM usage)
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! 12:00
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! Hash Cond:
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! Join Filter: ...
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! 13:00 - double-batches (not feet into RAM, use tmp-files)
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! 17:00 Hash (...)
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! Buckets: ... Batches: 4 ...
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! Buffers: ..., temp written=5217
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p6 - Inner Loop Join of 20:35
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https://www.youtube.com/watch?v=VeGJAQo9ogM
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! Bitmap Index Scan
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! Heap Blocks: exact=4413 (we have enough RAM)
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! ... lossy=3989 (non-precise fragments, contains links to table segments for re-check)
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! !! set/reset workmem
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! 4:00 select a.title, s.name
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! from albums a join songs s on a.id = s.a_id;
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! Nested Loop - node of plan
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! 12:00 select * from aircrafts a left join seats s on (a.aircraft_code = s.aircraft_code) where a.model like '...';
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! Nested Loop Left Join - node of plan
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! 19:00 nested-loop-join is effective on middle/sized cardinality only (for big ones need index)
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! + join can be done on anly condition
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p5 - Bitmap Scan 0:00 of 25:57
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https://www.youtube.com/watch?v=j7e7EANyJhE
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p4 - Inex Scan of 41:10
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https://www.youtube.com/watch?v=iu35dYTchu4
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! 8:00 select current_setting('random_page_cost'); -> 4
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! !!! need to decrease in case of ssd-disks
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! current_setting
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! 'random_page_cost'
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! 'seq_page_cost'
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! 'cpu_tuple_cost'
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! 'cpu_index_tuple_cost'
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! 'cpu_operator_cost'
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! 18:00 - other params
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! min_parallel_index_scan_size
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! ...per_...
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! 26:00 - create index ... include(...)
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! 33:00 - duplicate index records
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! 34:30 - pg has dup-idx-records exclusion mechanism (works only upon index-page-split)
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! create index ... with(deduplicate_items=off) -- to switchi it off
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! 37:00 - set enable_seqscan = off; -- to temporary disable seqscan
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p3 - Sequential Scan of 47:06
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https://www.youtube.com/watch?v=X2DOIf0DfJ0
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! parallel processing is not-efficitent for full seq-load, but is effective for the case of agg-n
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! "Parallel Seq Scan" -> "Partial Aggregate" -> "Gather"
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! 34:00 set max_parallel_workers_per_gather = 5;
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! 46:00 "post_parallel_mode" - allows to check whether query can be paral-d in principle
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p2 - Query Execution of 43:14
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https://www.youtube.com/watch?v=_6ce4YFFScc
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! 26:00 - set jit = off;
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! prepare model(varchar) as select model from aircrafts where iircraft_code = $1;
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! select * from pg_prepared_systems;
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! deallocate ... (or just close session)
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! 27:00 - declare c cursor for select * from aircrafts;
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! fetch c; ... close c;
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p1 - Air Demobase of 30:07
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https://www.youtube.com/watch?v=k9cloEiIPC0
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p0 - Intro of 8:49
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https://www.youtube.com/watch?v=2-UmottNWWk
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2022
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PostgresProfessional - Hacking PostgreSQL of p8
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6Jfb8IBNk3hZ07dxMxjfGtv
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! need to look
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2021
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PostgresProfessional - Rogov - DEV2 of 21 videos
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6K3AyBVcZGdXMtM2xvjHA1N
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https://postgrespro.ru/education/courses/DEV2
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PostgresProfessional - Rogov - Luzanov - Bashtaev - DBA1 Administration of 19 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6LPcuYVymLcXl3muC45mu3e
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https://postgrespro.ru/education/courses/DBA1
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2019
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PostgresProfessional - DBA3 Administration of 9 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6KEakTSrRWrekNI-z9U1ypF
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https://postgrespro.ru/education/courses/DBA3
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PostgresProfessional - DBA2 Administration of 18 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6KycrRthIC6mESoLLQen1k6
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https://postgrespro.ru/education/courses/DBA2
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PostgresProfessional - DBA1 Administration of 19 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6KycrRthIC6mESoLLQen1k6
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PostgresProfessional - Rogov - Luzanov - DBA1 Administration of 19 parts
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6JhHBp07QSu9uE8zahhKnTn
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https://postgrespro.ru/education/courses/DBA1
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Morgunov - sqlprimer
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6J1NEI8hjYlvGnD4Y7Sxx4r
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https://postgrespro.ru/education/university/sqlprimer
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https://edu.postgrespro.ru/sqlprimer/sqlprimer-2019-msu-03.pdf
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https://edu.postgrespro.ru/sqlprimer/sqlprimer-2019-msu-04.pdf
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Novikov
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https://edu.postgrespro.ru/dbtech/
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6K5maTyTF2NdcbpNsPHRecu
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2018
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PostgresProfessional - Rogov - Luzanov - DEV1 of 21 videos
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https://www.youtube.com/playlist?list=PLaFqU3KCWw6LNR1IZ814whJe89J1tRQ3t
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https://postgrespro.ru/education/courses/DEV1
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