> ALTER TABLE events ADD COLUMN version INT DEFAULT 1;
I’ve always disliked this approach. It conflates two things: the value to put in preexisting rows and the default going forward. I often want to add a column, backfill it, and not have a default.
Fortunately, the Iceberg spec at least got this right under the hood. There’s “initial-default”, which is the value implicitly inserted in rows that predate the addition of the column, and there’s “write-default”, which is the default for new rows.
hodgesrm · 4h ago
This Google article was nice as a high level overview of Iceberg V3. I wish that the V3 spec (and Iceberg specs in general) were more readable. For now the best approach seems to be read the Javadoc for the Iceberg Java API. [0]
To the contrary, the Delta Lake paper is extremely easy to read and implement the basics of (I did) and Iceberg has nothing so concise and clear.
twoodfin · 7m ago
If I implement what’s described in the Delta Lake paper, will I be able to query and update arbitrary Delta Lake tables as populated by Databricks in 2025?
(Would be genuinely excited if the answer is yes.)
eatonphil · 6m ago
Not sure (probably not). But it's definitely much easier to immediately understand IMO.
robertlagrant · 1h ago
> default column values
The way they implemented this seems really useful for any database.
drivenextfunc · 3h ago
Many companies seem to be using Apache Iceberg, but the ecosystem feels immature outside of Java. For instance, iceberg-rust doesn't even support HDFS. (Though admittedly, Iceberg's tendency to create many small files makes it a poor fit for HDFS anyway.)
ozgrakkurt · 32m ago
This was the same with arrow/parquet libraries as well. It takes a long time for all implementations to catch up
hodgesrm · 2h ago
Seems like this is going to be a permanent issue, no? Library level storage APIs are complex and often quite leaky. That's based on looking at the innards of MySQL and ClickHouse for a while.
It seems quite possible that there will be maybe three libraries that can write to Iceberg (Java, Python, Rust, maybe Golang), while the rest at best will offer read access only. And those language choices will condition and be conditioned by the languages that developers use to write applications that manage Iceberg data.
jamesblonde · 1h ago
When will open source v3 come out?
It's supposed to be in Apache Iceberg 1.10, right?
talatuyarer · 1h ago
Yes 1.10 version will be first version for V3 spec. But not all features are implemented on runners such as Spark or Flink.
Of course I haven't seen any implementations supporting these yet.
talatuyarer · 17m ago
Yes, the specification will be finalized with version 1.10. Previous versions also include specification changes. Iceberg's implementation of V3 occurs in three stages: Specification Change, Core Implementation, and Spark/Flink Implementation.
So far only Variant is supported in Spark and with 1.10 Spark will support nano timestamp and unknowntype I believe.
ahmetburhan · 3h ago
Cool to see Iceberg getting these kinds of upgrades. Deletion vectors and default column values sound like real quality-of-life improvements, especially for big, messy datasets. Curious to hear if anyone’s tried V3 in production yet and what the performance looks like.
jamesblonde · 1h ago
Is it out yet?
talatuyarer · 5h ago
This new version has some great new features, including deletion vectors for more efficient transactions and default column values to make schema evolution a breeze. The full article has all the details.
I’ve always disliked this approach. It conflates two things: the value to put in preexisting rows and the default going forward. I often want to add a column, backfill it, and not have a default.
Fortunately, the Iceberg spec at least got this right under the hood. There’s “initial-default”, which is the value implicitly inserted in rows that predate the addition of the column, and there’s “write-default”, which is the default for new rows.
[0] https://javadoc.io/doc/org.apache.iceberg/iceberg-api/latest...
https://github.com/delta-io/delta/blob/master/PROTOCOL.md
(Would be genuinely excited if the answer is yes.)
The way they implemented this seems really useful for any database.
It seems quite possible that there will be maybe three libraries that can write to Iceberg (Java, Python, Rust, maybe Golang), while the rest at best will offer read access only. And those language choices will condition and be conditioned by the languages that developers use to write applications that manage Iceberg data.
Of course I haven't seen any implementations supporting these yet.
So far only Variant is supported in Spark and with 1.10 Spark will support nano timestamp and unknowntype I believe.