Postgres FM

Nikolay Samokhvalov and Michael Christofides

A weekly podcast about all things PostgreSQL

  1. 4 NGÀY TRƯỚC

    When not to use Postgres

    Nik and Michael discuss when not to use Postgres — specifically use cases where it still makes sense to store data in another system. Here are some links to things they mentioned: Just use Postgres (blog post by Ethan McCue) https://mccue.dev/pages/8-16-24-just-use-postgresJust Use Postgres for Everything (blog post by Stephan Schmidt) https://www.amazingcto.com/postgres-for-everythingReal-time analytics episode https://postgres.fm/episodes/real-time-analyticsCrunchy Data Joins Snowflake https://www.crunchydata.com/blog/crunchy-data-joins-snowflakeTwo sizes fit most: PostgreSQL and Clickhouse (blog post by Sid Sijbrandij) https://about.gitlab.com/blog/two-sizes-fit-most-postgresql-and-clickhousepg_duckdb episode https://postgres.fm/episodes/pg_duckdbCloudberry https://github.com/apache/cloudberryTime-series considerations episode https://postgres.fm/episodes/time-series-considerationsQueues in Postgres episode https://postgres.fm/episodes/queues-in-postgresLarge Objects https://www.postgresql.org/docs/current/largeobjects.html PGlite https://pglite.devParadeDB https://www.paradedb.comZomboDB https://github.com/zombodb/zombodbturbopuffer https://turbopuffer.comHNSW vs. DiskANN (blog post by Haziqa Sajid) https://www.tigerdata.com/learn/hnsw-vs-diskannSPANN: Highly-efficient Billion-scale Approximate Nearest Neighbor Search (paper) https://www.microsoft.com/en-us/research/wp-content/uploads/2021/11/SPANN_finalversion1.pdfAmazon S3 Vectors https://aws.amazon.com/s3/features/vectorsIterative Index Scans added to pgvector in 0.8.0 https://github.com/pgvector/pgvector/issues/678S3 FDW from Supabase https://github.com/supabase/wrappers/tree/main/wrappers/src/fdw/s3_fdw ~~~ What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc! ~~~ Postgres FM is produced by: Michael Christofides, founder of pgMustardNikolay Samokhvalov, founder of Postgres.ai With credit to: Jessie Draws for the elephant artwork

    46 phút
  2. 18 THG 7

    MultiXact member space exhaustion

    Nikolay and Michael are joined by Andrew Johnson and Nate Brennand from Metronome to discuss MultiXact member space exhaustion — what it is, how they managed to hit it, and some tips to prevent running into it at scale. Here are some links to things they mentioned: Nate Brennand https://postgres.fm/people/nate-brennandAndrew Johnson https://postgres.fm/people/andrew-johnsonMetronome https://metronome.comRoot Cause Analysis: PostgreSQL MultiXact member exhaustion incidents (blog post by Metronome) https://metronome.com/blog/root-cause-analysis-postgresql-multixact-member-exhaustion-incidents-may-2025Multixacts and Wraparound (docs) https://www.postgresql.org/docs/current/routine-vacuuming.html#VACUUM-FOR-MULTIXACT-WRAPAROUNDmultixact.c source code https://github.com/postgres/postgres/blob/master/src/backend/access/transam/multixact.cAdd pg_stat_multixact view for multixact membership usage monitoring (patch proposal by Andrew, needing review!) https://commitfest.postgresql.org/patch/5869/PostgreSQL subtransactions considered harmful (blog post by Nikolay) https://postgres.ai/blog/20210831-postgresql-subtransactions-considered-harmfulvacuum_multixact_failsafe_age doesn't account for MultiXact member exhaustion (thread started by Peter Geoghegan) https://www.postgresql.org/message-id/flat/CAH2-WzmLPWJk3gbAxy8dHY%2BA-Juz_6uGwfe6DkE8B5-dTDvLcw%40mail.gmail.comAmazon S3 Vectors https://aws.amazon.com/blogs/aws/introducing-amazon-s3-vectors-first-cloud-storage-with-native-vector-support-at-scale/MultiXacts in PostgreSQL: usage, side effects, and monitoring (blog post by Shawn McCoy and Divya Sharma from AWS) https://aws.amazon.com/blogs/database/multixacts-in-postgresql-usage-side-effects-and-monitoring/Postgres Aurora multixact monitoring queries https://gist.github.com/natebrennand/0924f723ff61fa897c4106379fc7f3dc And finally an apology and a correction, the membership space is ~4B, not ~2B as said by Michael in the episode! Definition here:https://github.com/postgres/postgres/blob/f6ffbeda00e08c4c8ac8cf72173f84157491bfde/src/include/access/multixact.h#L31And here's the formula discussed for calculating how the member space can grow quadratically by the number of overlapping transactions: Members can be calculated via: aₙ = 2 + [sum from k=3 to n+1 of k]This simplifies to: aₙ = (((n+1)(n+2))/2) - 1 ~~~ What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc! ~~~ Postgres FM is produced by: Michael Christofides, founder of pgMustardNikolay Samokhvalov, founder of Postgres.ai With special thanks to: Jessie Draws for the elephant artwork

    56 phút
  3. 11 THG 7

    Multigres

    Nikolay and Michael are joined by Sugu Sougoumarane to discuss Multigres — a project he's joined Supabase to lead, building an adaptation of Vitess for Postgres! Here are some links to things they mentioned: Sugu Sougoumarane https://postgres.fm/people/sugu-sougoumaraneSupabase https://supabase.comAnnouncing Multigres https://supabase.com/blog/multigres-vitess-for-postgresVitess https://github.com/vitessio/vitessSPQR https://github.com/pg-sharding/spqrCitus https://github.com/citusdata/citusPgDog https://github.com/pgdogdev/pgdogMyths and Truths about Synchronous Replication in PostgreSQL (talk by Alexander Kukushkin) https://www.youtube.com/watch?v=PFn9qRGzTMcConsensus algorithms at scale (8 part series by Sugu) https://planetscale.com/blog/consensus-algorithms-at-scale-part-1A More Flexible Paxos (blog post by Sugu) https://www.sougou.io/a-more-flexible-paxoslibpg_query https://github.com/pganalyze/libpg_queryPL/Proxy https://github.com/plproxy/plproxyPlanetScale Postgres Benchmarking https://planetscale.com/blog/benchmarking-postgresMultiXact member exhaustion incidents (blog post by Cosmo Wolfe / Metronome) https://metronome.com/blog/root-cause-analysis-postgresql-multixact-member-exhaustion-incidents-may-2025 ~~~ What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc! ~~~ Postgres FM is produced by: Michael Christofides, founder of pgMustardNikolay Samokhvalov, founder of Postgres.ai With special thanks to: Jessie Draws for the elephant artwork

    1 giờ 19 phút
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A weekly podcast about all things PostgreSQL

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