Feature: Greenplum, Materialize compatibility/support for better performance

[rrjanbiah]

Context

1. When permissions are used, Hasura's performance is affected. Can reproduce it with simple permissions set up and through slow query log. Possibly related tickets are MaterializeInc/materialize#1008 MaterializeInc/materialize#3672 (Had to turn off permissions)
2. Even without permissions setup, Hasura API calls become too slow after continuously running for a day. Looks like the bottleneck is with Postgres as restarting it brings back to normal speed. So, while searching for this particular issue, came across couple of interesting links that suggest that Postgres may not be best suitable for all cases (our case is real-time update through WebSocket) and some workaround or alternative forks required.

\1. https://news.ycombinator.com/item?id=22767703

I’m assuming anyone who has to make that decision already knows this but, while PostgreSQL is great to host a production database, it isn’t a great choice for an analytic database at scale, or to train or store your machine learning features. It works, but it’s not great at scale.

\2. https://news.ycombinator.com/item?id=22771062

There are a lot of products that either fork or directly extend PostgreSQL for OLAP workloads. Greenplum[0], Materialize[1], Citus[2], PipelineDB[3] etc etc. [0] https://greenplum.org/

[1] https://materialize.io/

[2] https://www.citusdata.com/ (edit: I said TimescaleDB, I was thinking of Citus)

[3] https://github.com/pipelinedb/pipelinedb

\3. https://news.ycombinator.com/item?id=22775330 - PostgreSQL's Imperfections - Multiple discussions suggesting from pgbouncer, etc

[tirumaraiselvan]

Hi

1. When permissions are used, Hasura's performance is affected. Can reproduce it with simple permissions set up and through slow

Permissions will add a slight overhead (to check the permissions) but it should be very less. Can you post any numbers that you might be observing?

2. Even without permissions setup, Hasura API calls become too slow after continuously running for a day. Looks like the bottleneck is with Postgres as restarting it brings back to normal speed. So, while searching for this particular issue, came across couple of interesting links that suggest that Postgres may not be best suitable for all cases (our case is real-time update through WebSocket) and some workaround or alternative forks required.

Hmm. This is interesting. Could you point to these links? Maybe there are postgres configuration like VACCUM frequency etc that can be configured for optimal performance.

Having said that, Greenplum is an interesting database for Hasura to support in the future. We will keep it in mind.

[rrjanbiah]

Permissions will add a slight overhead (to check the permissions) but it should be very less. Can you post any numbers that you might be observing?

Hmm.... It seems to be easy to reproduce. For example, todos table has many relationship with users table (Array relationships). Both todos and users tables are set permissions in Hasura console ( say /console/data/schema/public/tables/todos/permissions and /console/data/schema/public/tables/users/permissions) with roles admin, 1, 2... with different insert, etc permissions set. When you query todos with users, it is too slow. Must be 100x or more.

Hmm. This is interesting. Could you point to these links? Maybe there are postgres configuration like VACCUM frequency etc that can be configured for optimal performance.

Please find.

postgresql.conf

```ini # ----------------------------- # PostgreSQL configuration file # ----------------------------- # # This file consists of lines of the form: # # name = value # # (The "=" is optional.) Whitespace may be used. Comments are introduced with # "#" anywhere on a line. The complete list of parameter names and allowed # values can be found in the PostgreSQL documentation. # # The commented-out settings shown in this file represent the default values. # Re-commenting a setting is NOT sufficient to revert it to the default value; # you need to reload the server. # # This file is read on server startup and when the server receives a SIGHUP # signal. If you edit the file on a running system, you have to SIGHUP the # server for the changes to take effect, run "pg_ctl reload", or execute # "SELECT pg_reload_conf()". Some parameters, which are marked below, # require a server shutdown and restart to take effect. # # Any parameter can also be given as a command-line option to the server, e.g., # "postgres -c log_connections=on". Some parameters can be changed at run time # with the "SET" SQL command. # # Memory units: kB = kilobytes Time units: ms = milliseconds # MB = megabytes s = seconds # GB = gigabytes min = minutes # TB = terabytes h = hours # d = days #------------------------------------------------------------------------------ # FILE LOCATIONS #------------------------------------------------------------------------------ # The default values of these variables are driven from the -D command-line # option or PGDATA environment variable, represented here as ConfigDir. #data_directory = 'ConfigDir' # use data in another directory # (change requires restart) #hba_file = 'ConfigDir/pg_hba.conf' # host-based authentication file # (change requires restart) #ident_file = 'ConfigDir/pg_ident.conf' # ident configuration file # (change requires restart) # If external_pid_file is not explicitly set, no extra PID file is written. #external_pid_file = '' # write an extra PID file # (change requires restart) #------------------------------------------------------------------------------ # CONNECTIONS AND AUTHENTICATION #------------------------------------------------------------------------------ # - Connection Settings - listen_addresses = '*' # what IP address(es) to listen on; # comma-separated list of addresses; # defaults to 'localhost'; use '*' for all # (change requires restart) port = 5432 # (change requires restart) max_connections = 100 # (change requires restart) #superuser_reserved_connections = 3 # (change requires restart) #unix_socket_directories = '/var/run/postgresql, /tmp' # comma-separated list of directories # (change requires restart) #unix_socket_group = '' # (change requires restart) #unix_socket_permissions = 0777 # begin with 0 to use octal notation # (change requires restart) #bonjour = off # advertise server via Bonjour # (change requires restart) #bonjour_name = '' # defaults to the computer name # (change requires restart) # - TCP Keepalives - # see "man 7 tcp" for details #tcp_keepalives_idle = 0 # TCP_KEEPIDLE, in seconds; # 0 selects the system default #tcp_keepalives_interval = 0 # TCP_KEEPINTVL, in seconds; # 0 selects the system default #tcp_keepalives_count = 0 # TCP_KEEPCNT; # 0 selects the system default # - Authentication - #authentication_timeout = 1min # 1s-600s #password_encryption = md5 # md5 or scram-sha-256 #db_user_namespace = off # GSSAPI using Kerberos #krb_server_keyfile = '' #krb_caseins_users = off # - SSL - #ssl = off #ssl_ca_file = '' #ssl_cert_file = 'server.crt' #ssl_crl_file = '' #ssl_key_file = 'server.key' #ssl_ciphers = 'HIGH:MEDIUM:+3DES:!aNULL' # allowed SSL ciphers #ssl_prefer_server_ciphers = on #ssl_ecdh_curve = 'prime256v1' #ssl_dh_params_file = '' #ssl_passphrase_command = '' #ssl_passphrase_command_supports_reload = off #------------------------------------------------------------------------------ # RESOURCE USAGE (except WAL) #------------------------------------------------------------------------------ # - Memory - shared_buffers = 128MB # min 128kB # (change requires restart) #huge_pages = try # on, off, or try # (change requires restart) #temp_buffers = 8MB # min 800kB #max_prepared_transactions = 0 # zero disables the feature # (change requires restart) # Caution: it is not advisable to set max_prepared_transactions nonzero unless # you actively intend to use prepared transactions. #work_mem = 4MB # min 64kB #maintenance_work_mem = 64MB # min 1MB #autovacuum_work_mem = -1 # min 1MB, or -1 to use maintenance_work_mem #max_stack_depth = 2MB # min 100kB dynamic_shared_memory_type = posix # the default is the first option # supported by the operating system: # posix # sysv # windows # mmap # use none to disable dynamic shared memory # (change requires restart) # - Disk - #temp_file_limit = -1 # limits per-process temp file space # in kB, or -1 for no limit # - Kernel Resources - #max_files_per_process = 1000 # min 25 # (change requires restart) # - Cost-Based Vacuum Delay - #vacuum_cost_delay = 0 # 0-100 milliseconds #vacuum_cost_page_hit = 1 # 0-10000 credits #vacuum_cost_page_miss = 10 # 0-10000 credits #vacuum_cost_page_dirty = 20 # 0-10000 credits #vacuum_cost_limit = 200 # 1-10000 credits # - Background Writer - #bgwriter_delay = 200ms # 10-10000ms between rounds #bgwriter_lru_maxpages = 100 # max buffers written/round, 0 disables #bgwriter_lru_multiplier = 2.0 # 0-10.0 multiplier on buffers scanned/round #bgwriter_flush_after = 512kB # measured in pages, 0 disables # - Asynchronous Behavior - #effective_io_concurrency = 1 # 1-1000; 0 disables prefetching #max_worker_processes = 8 # (change requires restart) #max_parallel_maintenance_workers = 2 # taken from max_parallel_workers #max_parallel_workers_per_gather = 2 # taken from max_parallel_workers #parallel_leader_participation = on #max_parallel_workers = 8 # maximum number of max_worker_processes that # can be used in parallel operations #old_snapshot_threshold = -1 # 1min-60d; -1 disables; 0 is immediate # (change requires restart) #backend_flush_after = 0 # measured in pages, 0 disables #------------------------------------------------------------------------------ # WRITE-AHEAD LOG #------------------------------------------------------------------------------ # - Settings - #wal_level = replica # minimal, replica, or logical # (change requires restart) #fsync = on # flush data to disk for crash safety # (turning this off can cause # unrecoverable data corruption) #synchronous_commit = on # synchronization level; # off, local, remote_write, remote_apply, or on #wal_sync_method = fsync # the default is the first option # supported by the operating system: # open_datasync # fdatasync (default on Linux) # fsync # fsync_writethrough # open_sync #full_page_writes = on # recover from partial page writes #wal_compression = off # enable compression of full-page writes #wal_log_hints = off # also do full page writes of non-critical updates # (change requires restart) #wal_buffers = -1 # min 32kB, -1 sets based on shared_buffers # (change requires restart) #wal_writer_delay = 200ms # 1-10000 milliseconds #wal_writer_flush_after = 1MB # measured in pages, 0 disables #commit_delay = 0 # range 0-100000, in microseconds #commit_siblings = 5 # range 1-1000 # - Checkpoints - #checkpoint_timeout = 5min # range 30s-1d max_wal_size = 1GB min_wal_size = 80MB #checkpoint_completion_target = 0.5 # checkpoint target duration, 0.0 - 1.0 #checkpoint_flush_after = 256kB # measured in pages, 0 disables #checkpoint_warning = 30s # 0 disables # - Archiving - #archive_mode = off # enables archiving; off, on, or always # (change requires restart) #archive_command = '' # command to use to archive a logfile segment # placeholders: %p = path of file to archive # %f = file name only # e.g. 'test ! -f /mnt/server/archivedir/%f && cp %p /mnt/server/archivedir/%f' #archive_timeout = 0 # force a logfile segment switch after this # number of seconds; 0 disables #------------------------------------------------------------------------------ # REPLICATION #------------------------------------------------------------------------------ # - Sending Servers - # Set these on the master and on any standby that will send replication data. #max_wal_senders = 10 # max number of walsender processes # (change requires restart) #wal_keep_segments = 0 # in logfile segments; 0 disables #wal_sender_timeout = 60s # in milliseconds; 0 disables #max_replication_slots = 10 # max number of replication slots # (change requires restart) #track_commit_timestamp = off # collect timestamp of transaction commit # (change requires restart) # - Master Server - # These settings are ignored on a standby server. #synchronous_standby_names = '' # standby servers that provide sync rep # method to choose sync standbys, number of sync standbys, # and comma-separated list of application_name # from standby(s); '*' = all #vacuum_defer_cleanup_age = 0 # number of xacts by which cleanup is delayed # - Standby Servers - # These settings are ignored on a master server. #hot_standby = on # "off" disallows queries during recovery # (change requires restart) #max_standby_archive_delay = 30s # max delay before canceling queries # when reading WAL from archive; # -1 allows indefinite delay #max_standby_streaming_delay = 30s # max delay before canceling queries # when reading streaming WAL; # -1 allows indefinite delay #wal_receiver_status_interval = 10s # send replies at least this often # 0 disables #hot_standby_feedback = off # send info from standby to prevent # query conflicts #wal_receiver_timeout = 60s # time that receiver waits for # communication from master # in milliseconds; 0 disables #wal_retrieve_retry_interval = 5s # time to wait before retrying to # retrieve WAL after a failed attempt # - Subscribers - # These settings are ignored on a publisher. #max_logical_replication_workers = 4 # taken from max_worker_processes # (change requires restart) #max_sync_workers_per_subscription = 2 # taken from max_logical_replication_workers #------------------------------------------------------------------------------ # QUERY TUNING #------------------------------------------------------------------------------ # - Planner Method Configuration - #enable_bitmapscan = on #enable_hashagg = on #enable_hashjoin = on #enable_indexscan = on #enable_indexonlyscan = on #enable_material = on #enable_mergejoin = on #enable_nestloop = on #enable_parallel_append = on #enable_seqscan = on #enable_sort = on #enable_tidscan = on #enable_partitionwise_join = off #enable_partitionwise_aggregate = off #enable_parallel_hash = on #enable_partition_pruning = on # - Planner Cost Constants - #seq_page_cost = 1.0 # measured on an arbitrary scale random_page_cost = 1.0 # same scale as above #cpu_tuple_cost = 0.01 # same scale as above #cpu_index_tuple_cost = 0.005 # same scale as above #cpu_operator_cost = 0.0025 # same scale as above #parallel_tuple_cost = 0.1 # same scale as above #parallel_setup_cost = 1000.0 # same scale as above #jit_above_cost = 100000 # perform JIT compilation if available # and query more expensive than this; # -1 disables #jit_inline_above_cost = 500000 # inline small functions if query is # more expensive than this; -1 disables #jit_optimize_above_cost = 500000 # use expensive JIT optimizations if # query is more expensive than this; # -1 disables #min_parallel_table_scan_size = 8MB #min_parallel_index_scan_size = 512kB #effective_cache_size = 4GB # - Genetic Query Optimizer - #geqo = on #geqo_threshold = 12 #geqo_effort = 5 # range 1-10 #geqo_pool_size = 0 # selects default based on effort #geqo_generations = 0 # selects default based on effort #geqo_selection_bias = 2.0 # range 1.5-2.0 #geqo_seed = 0.0 # range 0.0-1.0 # - Other Planner Options - #default_statistics_target = 100 # range 1-10000 #constraint_exclusion = partition # on, off, or partition #cursor_tuple_fraction = 0.1 # range 0.0-1.0 #from_collapse_limit = 8 #join_collapse_limit = 8 # 1 disables collapsing of explicit # JOIN clauses #force_parallel_mode = off #jit = off # allow JIT compilation #------------------------------------------------------------------------------ # REPORTING AND LOGGING #------------------------------------------------------------------------------ # - Where to Log - log_destination = 'stderr' # Valid values are combinations of # stderr, csvlog, syslog, and eventlog, # depending on platform. csvlog # requires logging_collector to be on. # This is used when logging to stderr: logging_collector = on # Enable capturing of stderr and csvlog # into log files. Required to be on for # csvlogs. # (change requires restart) # These are only used if logging_collector is on: log_directory = 'log' # directory where log files are written, # can be absolute or relative to PGDATA log_filename = 'postgresql-%a.log' # log file name pattern, # can include strftime() escapes #log_file_mode = 0600 # creation mode for log files, # begin with 0 to use octal notation log_truncate_on_rotation = on # If on, an existing log file with the # same name as the new log file will be # truncated rather than appended to. # But such truncation only occurs on # time-driven rotation, not on restarts # or size-driven rotation. Default is # off, meaning append to existing files # in all cases. log_rotation_age = 1d # Automatic rotation of logfiles will # happen after that time. 0 disables. log_rotation_size = 0 # Automatic rotation of logfiles will # happen after that much log output. # 0 disables. # These are relevant when logging to syslog: #syslog_facility = 'LOCAL0' #syslog_ident = 'postgres' #syslog_sequence_numbers = on #syslog_split_messages = on # This is only relevant when logging to eventlog (win32): # (change requires restart) #event_source = 'PostgreSQL' # - When to Log - #log_min_messages = warning # values in order of decreasing detail: # debug5 # debug4 # debug3 # debug2 # debug1 # info # notice # warning # error # log # fatal # panic #log_min_error_statement = error # values in order of decreasing detail: # debug5 # debug4 # debug3 # debug2 # debug1 # info # notice # warning # error # log # fatal # panic (effectively off) #log_min_duration_statement = -1 # -1 is disabled, 0 logs all statements # and their durations, > 0 logs only # statements running at least this number # of milliseconds # - What to Log - #debug_print_parse = off #debug_print_rewritten = off #debug_print_plan = off #debug_pretty_print = on #log_checkpoints = off #log_connections = off #log_disconnections = off #log_duration = off #log_error_verbosity = default # terse, default, or verbose messages #log_hostname = off log_line_prefix = '%m [%p] ' # special values: # %a = application name # %u = user name # %d = database name # %r = remote host and port # %h = remote host # %p = process ID # %t = timestamp without milliseconds # %m = timestamp with milliseconds # %n = timestamp with milliseconds (as a Unix epoch) # %i = command tag # %e = SQL state # %c = session ID # %l = session line number # %s = session start timestamp # %v = virtual transaction ID # %x = transaction ID (0 if none) # %q = stop here in non-session # processes # %% = '%' # e.g. '<%u%%%d> ' #log_lock_waits = off # log lock waits >= deadlock_timeout #log_statement = 'none' # none, ddl, mod, all #log_replication_commands = off #log_temp_files = -1 # log temporary files equal or larger # than the specified size in kilobytes; # -1 disables, 0 logs all temp files log_timezone = 'Europe/Amsterdam' #------------------------------------------------------------------------------ # PROCESS TITLE #------------------------------------------------------------------------------ #cluster_name = '' # added to process titles if nonempty # (change requires restart) #update_process_title = on #------------------------------------------------------------------------------ # STATISTICS #------------------------------------------------------------------------------ # - Query and Index Statistics Collector - #track_activities = on #track_counts = on #track_io_timing = off #track_functions = none # none, pl, all #track_activity_query_size = 1024 # (change requires restart) #stats_temp_directory = 'pg_stat_tmp' # - Monitoring - #log_parser_stats = off #log_planner_stats = off #log_executor_stats = off #log_statement_stats = off #------------------------------------------------------------------------------ # AUTOVACUUM #------------------------------------------------------------------------------ #autovacuum = on # Enable autovacuum subprocess? 'on' # requires track_counts to also be on. #log_autovacuum_min_duration = -1 # -1 disables, 0 logs all actions and # their durations, > 0 logs only # actions running at least this number # of milliseconds. #autovacuum_max_workers = 3 # max number of autovacuum subprocesses # (change requires restart) #autovacuum_naptime = 1min # time between autovacuum runs #autovacuum_vacuum_threshold = 50 # min number of row updates before # vacuum #autovacuum_analyze_threshold = 50 # min number of row updates before # analyze #autovacuum_vacuum_scale_factor = 0.2 # fraction of table size before vacuum #autovacuum_analyze_scale_factor = 0.1 # fraction of table size before analyze #autovacuum_freeze_max_age = 200000000 # maximum XID age before forced vacuum # (change requires restart) #autovacuum_multixact_freeze_max_age = 400000000 # maximum multixact age # before forced vacuum # (change requires restart) #autovacuum_vacuum_cost_delay = 20ms # default vacuum cost delay for # autovacuum, in milliseconds; # -1 means use vacuum_cost_delay #autovacuum_vacuum_cost_limit = -1 # default vacuum cost limit for # autovacuum, -1 means use # vacuum_cost_limit #------------------------------------------------------------------------------ # CLIENT CONNECTION DEFAULTS #------------------------------------------------------------------------------ # - Statement Behavior - #client_min_messages = notice # values in order of decreasing detail: # debug5 # debug4 # debug3 # debug2 # debug1 # log # notice # warning # error #search_path = '"$user", public' # schema names #row_security = on #default_tablespace = '' # a tablespace name, '' uses the default #temp_tablespaces = '' # a list of tablespace names, '' uses # only default tablespace #check_function_bodies = on #default_transaction_isolation = 'read committed' #default_transaction_read_only = off #default_transaction_deferrable = off #session_replication_role = 'origin' #statement_timeout = 0 # in milliseconds, 0 is disabled #lock_timeout = 0 # in milliseconds, 0 is disabled #idle_in_transaction_session_timeout = 0 # in milliseconds, 0 is disabled #vacuum_freeze_min_age = 50000000 #vacuum_freeze_table_age = 150000000 #vacuum_multixact_freeze_min_age = 5000000 #vacuum_multixact_freeze_table_age = 150000000 #vacuum_cleanup_index_scale_factor = 0.1 # fraction of total number of tuples # before index cleanup, 0 always performs # index cleanup #bytea_output = 'hex' # hex, escape #xmlbinary = 'base64' #xmloption = 'content' #gin_fuzzy_search_limit = 0 #gin_pending_list_limit = 4MB # - Locale and Formatting - datestyle = 'iso, mdy' #intervalstyle = 'postgres' timezone = 'Europe/Amsterdam' #timezone_abbreviations = 'Default' # Select the set of available time zone # abbreviations. Currently, there are # Default # Australia (historical usage) # India # You can create your own file in # share/timezonesets/. #extra_float_digits = 0 # min -15, max 3 #client_encoding = sql_ascii # actually, defaults to database # encoding # These settings are initialized by initdb, but they can be changed. lc_messages = 'en_US.UTF-8' # locale for system error message # strings lc_monetary = 'en_US.UTF-8' # locale for monetary formatting lc_numeric = 'en_US.UTF-8' # locale for number formatting lc_time = 'en_US.UTF-8' # locale for time formatting # default configuration for text search default_text_search_config = 'pg_catalog.english' # - Shared Library Preloading - #shared_preload_libraries = '' # (change requires restart) #local_preload_libraries = '' #session_preload_libraries = '' #jit_provider = 'llvmjit' # JIT library to use # - Other Defaults - #dynamic_library_path = '$libdir' #------------------------------------------------------------------------------ # LOCK MANAGEMENT #------------------------------------------------------------------------------ #deadlock_timeout = 1s #max_locks_per_transaction = 64 # min 10 # (change requires restart) #max_pred_locks_per_transaction = 64 # min 10 # (change requires restart) #max_pred_locks_per_relation = -2 # negative values mean # (max_pred_locks_per_transaction # / -max_pred_locks_per_relation) - 1 #max_pred_locks_per_page = 2 # min 0 #------------------------------------------------------------------------------ # VERSION AND PLATFORM COMPATIBILITY #------------------------------------------------------------------------------ # - Previous PostgreSQL Versions - #array_nulls = on #backslash_quote = safe_encoding # on, off, or safe_encoding #default_with_oids = off #escape_string_warning = on #lo_compat_privileges = off #operator_precedence_warning = off #quote_all_identifiers = off #standard_conforming_strings = on #synchronize_seqscans = on # - Other Platforms and Clients - #transform_null_equals = off #------------------------------------------------------------------------------ # ERROR HANDLING #------------------------------------------------------------------------------ #exit_on_error = off # terminate session on any error? #restart_after_crash = on # reinitialize after backend crash? #data_sync_retry = off # retry or panic on failure to fsync # data? # (change requires restart) #------------------------------------------------------------------------------ # CONFIG FILE INCLUDES #------------------------------------------------------------------------------ # These options allow settings to be loaded from files other than the # default postgresql.conf. #include_dir = '' # include files ending in '.conf' from # a directory, e.g., 'conf.d' #include_if_exists = '' # include file only if it exists #include = '' # include file #------------------------------------------------------------------------------ # CUSTOMIZED OPTIONS #------------------------------------------------------------------------------ # Add settings for extensions here shared_preload_libraries = 'pg_stat_statements' pg_stat_statements.track = all pg_stat_statements.max = 10000 track_activity_query_size = 2048 ```

[nishu]

+1 for the support for the materialize.io

[awang]

Does Hasura have the ability to "change out" the underlying engine? For example, we've written a Metabase driver that allowed us to quickly work around queries which aren't yet supported by Materialize: https://github.com/MaterializeInc/metabase-materialize-driver

[rrjanbiah]

@0x777 For your attention, please. Question from the Materialize team (@awang)

[rrjanbiah]

FWIW, linking https://github.com/MaterializeInc/database-issues/issues/1284