Tanel Poder
@tanelpoder.com
Creator of https://0x.tools, also a long-time computer performance geek. Perf & troubleshooting blog: tanelpoder.com. All onions are mine.
Pinned
Tanel Poder
@tanelpoder.com
· Nov 3
New blog: xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates)
tanelpoder.com/posts/xb-sql...
tanelpoder.com/posts/xb-sql...
Reposted by Tanel Poder
modern-sql.com now covers DuckDB.
Modern SQL: A lot has changed since SQL-92
SQL has evolved. Beyond the relational model. Discover it now.
modern-sql.com
November 28, 2025 at 1:24 PM
modern-sql.com now covers DuckDB.
Reposted by Tanel Poder
Happy Thanksgiving! Need a pod while washing dishes? New Oxide and Friends examines a bug introduced over 18 years ago. Performance is great but not—it turns out—without correctness oxide-and-friends.transistor.fm/episodes/gro...
Oxide and Friends | Grown-up ZFS Data Corruption Bug
Hey hey! We recently tripped over a ZFS data corruption bug–introduced over 18 years ago! Bryan and Adam discuss with members of the Oxide team as well as Matt Ahrens, the co-inventor of ZFS.In add...
oxide-and-friends.transistor.fm
November 27, 2025 at 9:43 PM
Happy Thanksgiving! Need a pod while washing dishes? New Oxide and Friends examines a bug introduced over 18 years ago. Performance is great but not—it turns out—without correctness oxide-and-friends.transistor.fm/episodes/gro...
(3 days left until the end of Black Friday Sale of my online training courses!)
Also, an old post for Oracle nerds:
"Oracle Shared Pool Internals: List Chunk Position in the LRU List"
tanelpoder.com/posts/oracle...
Also, an old post for Oracle nerds:
"Oracle Shared Pool Internals: List Chunk Position in the LRU List"
tanelpoder.com/posts/oracle...
November 28, 2025 at 7:14 PM
(3 days left until the end of Black Friday Sale of my online training courses!)
Also, an old post for Oracle nerds:
"Oracle Shared Pool Internals: List Chunk Position in the LRU List"
tanelpoder.com/posts/oracle...
Also, an old post for Oracle nerds:
"Oracle Shared Pool Internals: List Chunk Position in the LRU List"
tanelpoder.com/posts/oracle...
Reposted by Tanel Poder
When tuning #SQL, focus on the estimates for how many rows each operation will return
If these are off by an order of magnitude or more, there's a good chance a different plan is faster
@tanelpoder.com has built scripts to show misestimates in Oracle plans
If these are off by an order of magnitude or more, there's a good chance a different plan is faster
@tanelpoder.com has built scripts to show misestimates in Oracle plans
xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates) - Tanel Poder Consulting
Here’s part 3 of my xb.sql & xbi.sql article series that I started writing back in 2019 :-) Part 1 - Show and format execution plans by querying V$SQL_PLAN data directly Part 2 - Show plan line level…
buff.ly
November 26, 2025 at 12:01 PM
When tuning #SQL, focus on the estimates for how many rows each operation will return
If these are off by an order of magnitude or more, there's a good chance a different plan is faster
@tanelpoder.com has built scripts to show misestimates in Oracle plans
If these are off by an order of magnitude or more, there's a good chance a different plan is faster
@tanelpoder.com has built scripts to show misestimates in Oracle plans
One week left till the end of the Black Friday sale of my self-paced video learning courses! 🤓
I just extended the Black Friday sale to the whole month of November!
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
November 24, 2025 at 3:48 AM
One week left till the end of the Black Friday sale of my self-paced video learning courses! 🤓
Reposted by Tanel Poder
cool job at a very special computer company
- write TypeScript and Rust
- everyone makes $235k
- fully remote
- everything is open source
- write TypeScript and Rust
- everyone makes $235k
- fully remote
- everything is open source
Product Engineer / Oxide
oxide.computer
November 19, 2025 at 6:33 PM
cool job at a very special computer company
- write TypeScript and Rust
- everyone makes $235k
- fully remote
- everything is open source
- write TypeScript and Rust
- everyone makes $235k
- fully remote
- everything is open source
Reposted by Tanel Poder
Biggest takeaway from KubeCon: People want Neki badly.
We're building the solution for scaling and managing huge Postgres databases.
More to come, but in the meantime: neki.dev
We're building the solution for scaling and managing huge Postgres databases.
More to come, but in the meantime: neki.dev
Neki - Sign Up
Join Neki and stay updated with our latest news and updates.
neki.dev
November 14, 2025 at 5:40 PM
Biggest takeaway from KubeCon: People want Neki badly.
We're building the solution for scaling and managing huge Postgres databases.
More to come, but in the meantime: neki.dev
We're building the solution for scaling and managing huge Postgres databases.
More to come, but in the meantime: neki.dev
Reposted by Tanel Poder
Turns out you can communicate across containers via 63-bits of available space in a shared lock you acquire on /proc/self/ns/time that all processes have access to.
No networking required. The post has a demo of a chat app communicating across unprivileged containers.
h4x0r.org/funreliable/
No networking required. The post has a demo of a chat app communicating across unprivileged containers.
h4x0r.org/funreliable/
November 12, 2025 at 2:35 PM
Turns out you can communicate across containers via 63-bits of available space in a shared lock you acquire on /proc/self/ns/time that all processes have access to.
No networking required. The post has a demo of a chat app communicating across unprivileged containers.
h4x0r.org/funreliable/
No networking required. The post has a demo of a chat app communicating across unprivileged containers.
h4x0r.org/funreliable/
Reposted by Tanel Poder
Added a blog update about the V$PROCESS_MEMORY_DETAIL auto-population for processes with PGA growth to over 500MB. Enabled in Oracle 19.18+, so no "oradebug dump pga_get_detail" needed, just query the V$ views for a detailed "heapdump":
tanelpoder.com/2014/03/26/o...
tanelpoder.com/2014/03/26/o...
November 10, 2025 at 6:29 AM
Added a blog update about the V$PROCESS_MEMORY_DETAIL auto-population for processes with PGA growth to over 500MB. Enabled in Oracle 19.18+, so no "oradebug dump pga_get_detail" needed, just query the V$ views for a detailed "heapdump":
tanelpoder.com/2014/03/26/o...
tanelpoder.com/2014/03/26/o...
Reposted by Tanel Poder
New scripts: vstat.sql & dstat.sql for showing Oracle Sysmetric history with 1-minute granularity (both from AWR and regular V$ views)
tanelpoder.com/posts/oracle...
tanelpoder.com/posts/oracle...
November 10, 2025 at 5:52 AM
New scripts: vstat.sql & dstat.sql for showing Oracle Sysmetric history with 1-minute granularity (both from AWR and regular V$ views)
tanelpoder.com/posts/oracle...
tanelpoder.com/posts/oracle...
Added a blog update about the V$PROCESS_MEMORY_DETAIL auto-population for processes with PGA growth to over 500MB. Enabled in Oracle 19.18+, so no "oradebug dump pga_get_detail" needed, just query the V$ views for a detailed "heapdump":
tanelpoder.com/2014/03/26/o...
tanelpoder.com/2014/03/26/o...
November 10, 2025 at 6:29 AM
Added a blog update about the V$PROCESS_MEMORY_DETAIL auto-population for processes with PGA growth to over 500MB. Enabled in Oracle 19.18+, so no "oradebug dump pga_get_detail" needed, just query the V$ views for a detailed "heapdump":
tanelpoder.com/2014/03/26/o...
tanelpoder.com/2014/03/26/o...
New scripts: vstat.sql & dstat.sql for showing Oracle Sysmetric history with 1-minute granularity (both from AWR and regular V$ views)
tanelpoder.com/posts/oracle...
tanelpoder.com/posts/oracle...
November 10, 2025 at 5:52 AM
New scripts: vstat.sql & dstat.sql for showing Oracle Sysmetric history with 1-minute granularity (both from AWR and regular V$ views)
tanelpoder.com/posts/oracle...
tanelpoder.com/posts/oracle...
Reposted by Tanel Poder
FreeSQL.com now supports SQLNet connectivity for your free schema on both our 19c and 26ai database platforms.
FreeSQL.com
November 6, 2025 at 10:42 PM
FreeSQL.com now supports SQLNet connectivity for your free schema on both our 19c and 26ai database platforms.
Reposted by Tanel Poder
A bunch of folks at Oxide uncovered a tricky deadlock associated with async Rust (yes, another!), so--of [email protected] and I got the crew together to discuss. If you're writing async Rust, you'll want to know how to avoid and diagnose "Futurelock"
Oxide and Friends 11/3/2025 -- Futurelock
YouTube video by Oxide Computer Company
www.youtube.com
November 6, 2025 at 3:20 PM
A bunch of folks at Oxide uncovered a tricky deadlock associated with async Rust (yes, another!), so--of [email protected] and I got the crew together to discuss. If you're writing async Rust, you'll want to know how to avoid and diagnose "Futurelock"
Reposted by Tanel Poder
This post is awesome eavan.blog/posts/implem...
Please Implement This Simple SLO
eavan.blog
November 6, 2025 at 12:31 AM
This post is awesome eavan.blog/posts/implem...
Reposted by Tanel Poder
In concept I’m a huge fan of porting infrastructural code to Rust/memory safe languages, but shipping broken code — especially code that causes silent data loss — doesn’t help that cause.
`dd` incorrectly counts partial reads toward `count` limit, causing data loss in pipelines · Issue #9119 · uutils/coreutils
Summary uutils dd has a critical bug where partial reads from pipes are counted toward the count=N limit, causing premature termination and significant data loss. GNU dd correctly only counts full ...
github.com
November 5, 2025 at 11:28 PM
In concept I’m a huge fan of porting infrastructural code to Rust/memory safe languages, but shipping broken code — especially code that causes silent data loss — doesn’t help that cause.
Reposted by Tanel Poder
I just extended the Black Friday sale to the whole month of November!
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
November 2, 2025 at 9:45 PM
I just extended the Black Friday sale to the whole month of November!
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
Reposted by Tanel Poder
New blog: xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates)
tanelpoder.com/posts/xb-sql...
tanelpoder.com/posts/xb-sql...
November 3, 2025 at 7:48 AM
New blog: xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates)
tanelpoder.com/posts/xb-sql...
tanelpoder.com/posts/xb-sql...
New blog: xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates)
tanelpoder.com/posts/xb-sql...
tanelpoder.com/posts/xb-sql...
November 3, 2025 at 7:48 AM
New blog: xb.sql and xbi.sql - Explain Oracle Execution Plans Better! (Part 3 - Cardinality Misestimates)
tanelpoder.com/posts/xb-sql...
tanelpoder.com/posts/xb-sql...
I just extended the Black Friday sale to the whole month of November!
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
November 2, 2025 at 9:45 PM
I just extended the Black Friday sale to the whole month of November!
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
All my existing full-week flagship courses are heavily discounted for the entire month, and more content coming soon!
tanelpoder.com/posts/black-...
Reposted by Tanel Poder
If you want to do *online* database schema migrations without degrading the performance of your system, the Expand and Contract Pattern is a great approach. And generally a great pattern to know about.
www.prisma.io/dataguide/ty...
www.prisma.io/dataguide/ty...
Using the expand and contract pattern | Prisma's Data Guide
In this article, we introduce the expand and contract pattern to help migrate data and clients to a new schema.
www.prisma.io
October 31, 2025 at 6:52 PM
If you want to do *online* database schema migrations without degrading the performance of your system, the Expand and Contract Pattern is a great approach. And generally a great pattern to know about.
www.prisma.io/dataguide/ty...
www.prisma.io/dataguide/ty...
Reposted by Tanel Poder
My colleague Dave Pacheco wrote up a great description of a new (to us?) Rust async pathology--"futurelock"--another extremely sharp edge to watch out for, with no particular guardrails. Of course, we'll be talking about it with @bcantrill.bsky.social on Monday's Oxide and Friends
609 - Futurelock / RFD / Oxide
rfd.shared.oxide.computer
October 31, 2025 at 7:00 PM
My colleague Dave Pacheco wrote up a great description of a new (to us?) Rust async pathology--"futurelock"--another extremely sharp edge to watch out for, with no particular guardrails. Of course, we'll be talking about it with @bcantrill.bsky.social on Monday's Oxide and Friends
Reposted by Tanel Poder
The first deep dive in my new special-focus training series starts on Wednesday:
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
October 31, 2025 at 4:44 AM
The first deep dive in my new special-focus training series starts on Wednesday:
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
Reposted by Tanel Poder
ladies and gentlemen...we got him
October 30, 2025 at 7:10 PM
ladies and gentlemen...we got him
The first deep dive in my new special-focus training series starts on Wednesday:
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
October 31, 2025 at 4:44 AM
The first deep dive in my new special-focus training series starts on Wednesday:
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/
"Handling the Optimizer, Statistics and Workloads on Partitioned Tables in Oracle Databases" (5-6 Nov 2025 + Q&A followup sessions).
One demo table has 100k partitions ;-)
Sign up here:
tanelpoder.com/seminar/