Lifted all my dahlias a few days ago, just before the overnight temperature dropped to -4C. It's taking ages to clean off all the earth so that they can dry properly for overwintering.

Here's a golden oldie that MIGHT still be causing some errors in early versions of 19c - a POSSIBLE case appeared a few days ago on the Oracle database forum: jonathanlewis.wordpress.com/2015/11/09/w...

Only two weeks to go #ukougdiscover25 - don't stay up too late on Sunday night if you're thinking of coming to this one:

Now reading: "Blue Machine - How the ocean shapes our world" by @helenczerski.bsky.social A fascinating mix of scientific and historical detail, told in an enjoyable narrative style. Bought it after attending the 2nd in her series of lectures at Gresham College: www.gresham.ac.uk/watch-now/se...

Reference point for @oraclebase.bsky.social and @martinwidlake.bsky.social : the 2017 Ig Nobel prize for Physics was awarded to the author of a paper discussing whether cats are solids or liquids or both: live.stemfellowship.org/the-ig-nobel...

Thinking small but useful RESETTABLE, a recent (23.26, maybe older) v$ view seems to list resettable parameters: GV$SYSTEM_RESET_PARAMETER Name ------ INST_ID NUM NAME TYPE RESET_VALUE DISPLAY_RESET_VALUE ISSYS_RESETTABLE ISPDB_RESETTABLE ISINSTANCE_RESETTABLE UPDATE_COMMENT CON_ID

Small change, but so useful. RESETTABLE Clause to in Oracle AI Database 26ai oracle-base.com/articles/26/... @OracleDatabase #database #26ai

Special day on the allotment tomorrow. My order of raspberry canes has arrived from James McIntyre james-mcintyre.co.uk/product-cate... so I'll be hard at work in the fruit cage 5 x Glen Doll (floricane) 5 x All Gold (primocane) 8 x Joan J (primocane) with 2 "spare" Joan J for my old raspberry bed

Golden oldie time. From 2007 - and nearly answering a recent question about index sizing: thoughts about space and I/O requests when you are heading for billions of rows in the database. jonathanlewis.wordpress.com/2007/03/18/t...

How do you truncate a partition at the parent end of a referential integrity constraint? You can't (error ORA-02266) but someone asked how today so I pointed them to a workaround I described in 2012 (after testing to see if it still worked on 19.11) jonathanlewis.wordpress.com/2012/06/05/t...

Someone has just sent me a communication through chat. It must be someone I know because I've set chat to respond only to people I follow, and I don't follow many. But I can't use chat unless I supply my credit card number or a view of my face to an organisation I've never heard of - so no thanks.

Here's an article I published 12 years ago about rowids and sorting - if you store and report rowids the you will find that a columnn of type rowid sorts differently from a column where the rowid is stored in its character format. See: jonathanlewis.wordpress.com/2013/12/01/r... (Last tested 23.6)

Heads up VirtualBox. If you've updated to 7.2.4 and found that your VMs will no longer start (Error: Failed to load R0 module), then uninstall your existing installation first (or uninstall the 7.2.4 you just installed) and then install 7.2.4 from scratch

In the multitenant architecture in Oracle AI Database, the container database is essential. If you create it the right way, you can avoid some difficulties later on. Here's my recommendation for creating container databases.

Since last week, I can finally use the QUALIFY clause in Oracle. If you never heard of this SQL extension, read my newest blog post: danischnider.wordpress.com/2025/10/24/q...

Today I revisited a 4yo post on one of SQLcl’s underrated features: autotrace — shows full session stats for a SQL statement (way beyond SQL*Plus). Still works in latest release. Updated prereqs too. More details here 🔗 martincarstenbach.com/2021/06/10/s... #Oracle #SQLcl #performance #IKYK

A new post about parallel DML and how to waste huge amounts of space in your database in no time at all. jonathanlewis.wordpress.com/2025/10/10/m...

If you're in the mood to read a long and detailed article about shrinking indexes, here's one from 2022 that should meet your requirements: jonathanlewis.wordpress.com/2022/09/02/s...

Here's a note I wrote for redgate / simpletalk a few years ago about basic index compression - costs and benefits: www.red-gate.com/simple-talk/... It's part 5 of a series; part 4 was the technical bit about the mechanics of (basic) index compression. There's a link to it at the start of part 5.

Are you making any of these common #SQL mistakes? Forgetting about NULL Processing data in Java memory Using JDBC Pagination to paginate large results Using aggregate instead of window functions @lukaseder.bsky.social explains what to do instead & lists 7 more

Looks like it's not available anymore, my SR regarding this was closed with something like "Internal bug was submitted for investigation, but hey, we got that alternate features "Look-up By Error or Error Code's First Argument" or "Search by Stack Trace" added which replace it. For real?🤦‍♂️

This forum thread might be useful if you're playing around with 23ai and ONNX models (whatever they are) that don't come from Oracle Corp. forums.oracle.com/ords/apexds/... - particularly the comment from "Peter"

I'm on the agenda for the #ukoug conference 2025. 9:00 a.m. on Monday morning (I tell myself that that's to encourage people to be on-site early enough to attend the opening keynote afterwards) Abstract at: jonathanlewis.wordpress.com/public-appea...

A variant of this topic just appeared on one of the Oracle forums - what do you get for the rowid in a join view where you haven't explicitly selected any rowids? (In my case - which table gets the delete when you delete from a join view) jonathanlewis.wordpress.com/2022/05/31/j...

There are two ways I suprise myself when thinking about Oracle puzzles: 1) Struggling to unravel some internal detail then finding that I wrote about it 20 years ago 2) Discovering a "new" detail I should have noticed 20 years Here's an example of (2): jonathanlewis.wordpress.com/2025/09/29/r...

There's a problem on the oracle-l listserver at present about an insert taking far too much time (and CPU). It's a known issue and there are 47 statistics in v$sysstat (19.11) with names like 'ASSM%' to help diagnose it. How many do you think are described in the database reference manual? None.

A question on the Oracle db discusion forum asked for advice on using "alter index .... monitoring usage" in 19c. The correct advice is "don't use it, Oracle replaced it with 'index usage tracking' in 12.2 Pt 1 of 3: jonathanlewis.wordpress.com/2024/03/15/i... (links to pts 2 & 3 in the pingbacks)

Normally yes. If it asks for a bind value when running this then it uses varchar2 and causes the issue. It looks as if this happens only if you try to Run Script with a single SQL. Once there is more than 1 statement, it doesn't ask for bind and all is good.

TIL the SQL*Plus commands "document" and "set document on/off" became obsolete in 10.2 (But they still work, though go a bit funny in sqlcl)

If this treatment for Huntington's disease works out, this is going to be huge for those affected and their families. It’s another example of the legacy of the Human Genome project and the growing field of gene therapy. www.bbc.co.uk/news/article...

Blog post for September 2025 SQL Developer isn't entirely CBO-friendly. jonathanlewis.wordpress.com/2025/09/24/s...

Here's a fairly recent little note on parallel execution that came to mind while looking at a short list of parameter that had been supplied with a question on the oracle-l listserver about the limits of parallelism: jonathanlewis.wordpress.com/2022/09/09/p...

I'll be presenting at the UKOUG conference in Birmingham this year: jonathanlewis.wordpress.com/public-appea...

Just in from the MOSC forums: From 18th Sept Oracle will allow only corporate email addresses to be linked forum accounts - so it looks like I won’t be getting any more ‘most valued contributor’ awards.

Busy stewing up a large volume of apple and blackberry sauce. Apples from the orchard (i.e. back garden) and blackberries from the allotment.

There's a current thread on the MOS Forums (needs an account) suggesting that the 19.27 RU has introduced a bug that means the delete of expired auto_stats_advisor_tasks isn't doing a complete job. (Two separate sites discussing symptoms and workarounds). community.oracle.com/mosc/discuss...

Took a number of cuttings off a very healthy sage bush a couple of weeks ago and stuck them in a jam-jar of water. I've just potted up 7 which had grown a good set of roots, discarded 2 which had got nowhere, and left 2 in the jar to grow more roots - cutting back some of their leaves to help.

Went to @monikalewandowska.bsky.social presentation about nvl() at the #POUG2025 conference and had a conversation about an unexpected cardinality estimate - which didn't reproduce in my version of Oracle - but prompted me to revisit an ancient blog note: jonathanlewis.wordpress.com/2007/01/09/c...

How to open a Champagne bottle with an axe: leave it to someone else and make sure you’re standing far behind them

Reading this article reminded me that it was about time I checked a few examples of (old) concatenation / (new) "or expansion". One odd detail of the new feature is that it can't find a suitable predicate for expansion when a hint to use_concat() can jonathanlewis.wordpress.com/2023/01/30/l...

Sometimes it's just too hard to say no. I've just submitted an abstract for the UKOUG 2025 conference in Birmingham. (Nov 30 - Dec 2) The abstract is the same that I supplied for the Polish OUG 2025 (4th - 6th Sept) jonathanlewis.wordpress.com/public-appea...

There can be few things more satisfying to the gardener/allotmenteer than stepping out into the orchard (min 5 trees with no more than 20m between crown edges) to pick your own apples for the pot. Maybe picking oranges in your own Orangery - but mine isn't one of the stately homes of England.

Finished the draft of my presentation for #poug2025. Now have a week to cut it down from about 6 hours to something a lot nearer 40 minutes and polish (no pun intended) what's left.

Automatic error mitigation has arrived! BASIC idea: if the optimizer hits an ORA-00600 it looks for ways to bypass the code path that allowed the error to appear, generating a set of hints (like a SQL directive) to block the problem And it happens in real-time - so you don't know it was needed!

A long time ago I eliminated a lot of work from a batch update by pointing out that setting a flag to zero for 5M rows was a huge waste when all but a couple of hundred were already zero. Adding "where flag != 0" was a simple and (after careful checking) appropriate improvement to the code. But ...

Here's a question I posed a few years ago, and got a lot of interesting answers in the comments. Entertaining reading: jonathanlewis.wordpress.com/2009/11/12/n...

That's one of the little details I regularly fall back to re-read. I highly recommend it to everyone who ever think about object statistics further than #of-rows and ndv....

A question that's just appeared on the Oracle forums made me wonder how well known the table_cached_blocks preference for collecting object statistics was. If you don't know what it is then you need to read the 2nd half of this tip I wrote for IOUG 2015: jonathanlewis.wordpress.com/2021/09/20/o...

I've just (re-)discovered the 5 minute interview with Tanel Poder for the Virtual Conference he set up in 2020. I found it quite interesting to listen to - it makes a couple of interesting point in response to his leading question: www.youtube.com/watch?v=QQP7...

If you're using, or thinking of using, interval partitioning then you need to check whether this performance problem with bulk inserts it likely to be a problem: jonathanlewis.wordpress.com/2018/02/21/i... Last tested 19.11 and 23.6