- discuss - lists.mariadb.org

Which GSSAPI implementation should be used to compile mariadb-connector-c/cpp?
by 张天夫 16 Jan '25

16 Jan '25

I'm trying to compile mariadb-connector-c/cpp on Windows. However, Windows does not provide native GSSAPI. Do I need to look for other implementations? Which is the recommended implementation?

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Inquiry Regarding Parameters of Modified HNSW Algorithm in MariaDB Vector
by kase jojo 13 Jan '25

13 Jan '25

Dear Sir, I hope this message finds you well. I am currently working with the MariaDB vector functionality and am particularly interested in the modified HNSW (MHNSW) algorithm. Specifically, I would like to inquire about the meaning and usage of the parameter "M" in MHNSW, as well as how it compares to other HNSW implementations, such as pgvector. （ https://mariadb.com/kb/en/vector-system-variables/） Typically, HNSW has two key construction parameters: "M" and "efconstruction." However, I noticed that in MHNSW, there doesn't seem to be an "efc" parameter. This has led me to wonder if the "M" parameter in MHNSW has a different meaning or purpose compared to the traditional HNSW "M." Could you kindly clarify the role of the "M" parameter in the modified HNSW algorithm, and how it differs from or is similar to other implementations like pgvector? Thank you for your time and assistance. I look forward to your response. Best regards！

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MariaDb Master/Replica. How to recover replication when reverting Master to an earlier backup?
by Simon Avery 12 Jan '25

12 Jan '25

Hello We have two Mariadb 10.11.10 servers acting as Master and Replica. Both have unique local databases, plus seven that are replicated from Master to Replica with Replicate_Wild_Do_Table: DB1Name.%, DB2Name.% etc The size of the replicated databases is just over 1Tb, with the single largest being almost 500Gb. Both machines are in vmware and on the same network. Yesterday, we hit an issue with the Master which required that vm to be restored to a backup four hours previously. This got Master back in play, but obviously has broken Replication. Traditional wisdom seems to suggest that I need to recreate this replication setup from scratch - ie, stop Master (from changing, ie, close firewall and block clients, flush logs), note the Log Position, and then mysqldump each database. However, due to the size of these databases, that is going to take many hours and we can't accept that downtime for Master. It's occurred to us that we might speed this up by: Stop Master from changing. Note Log Position. Clone Master's vm to Master-Clone. (< 10 minutes) Restart Master. Then we would be at relative leisure to [On Clone] Mysqldump the databases onto a temporary drive. [On Replica] DROP the seven databases. Import the dumped databases from the temporary drive. Update the log position in config and restart the slave user. Then Replica should start syncing from Master again, even if Clone was several days old? Does that sound sensible? These databases have partitions - is that going to cause issues dumping and reimporting them or should I use another method? Any pitfalls? Any alternative ways? Thank you

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Re: Inquiry Regarding Slow Index Creation with MariaDB 11.7 RC (SIFT1M)
by Sergei Golubchik 12 Jan '25

12 Jan '25

Hi, kase, First: please send questions like this to discuss(a)lists.mariadb.org. it's a public mailing list dedicated to MariaDB and how to use it better. I am subscribed, so I'll see you mail there, and you may be sure I will, because it won't be accidentally catched by my spam filter, or sorted out in some obscure folder. Furthermore other subscribers will see your question and could reply if I will be not available (e.g. I could be travelling). Thank you. On Jan 12, kase jojo wrote: > Dear Sir > > I hope you are doing well. I recently read your blog > https://mariadb.com/resources/blog/how-fast-is-mariadb-vector/ and was > particularly impressed by the efficient index-building times demonstrated > in your tests. However, when I attempted similar experiments on MariaDB > 11.7 RC, using the SIFT1M dataset and building an index with M=32, I > noticed that the index creation process was much slower than expected. > > In my case, I have been inserting data into the table gradually, and I > wanted to inquire about the process you mentioned in your blog: "We > build the index slowly as we insert the data row by row." Could you > clarify how this process works? Specifically, I am curious to know if > there are any steps or techniques you followed to ensure such > efficient index construction, as it seems to differ from my > experience. To get faster inserts you need to use a smaller M. Try M=8, for example. It will reduce the recall, and you'll need to increase ef_search to compensate for that. Look at it this way: MariaDB needs to do the work to get good recall. It has to do it *somewhere*. But you can decide where to do it. MariaDB can spend more time doing inserts, build a better index, and search in it quickly. Or it can insert faster, the index will be of worse quality, and it'll need to spend more time searching in it. It's a trade-off and you decide what is more important for your application. See https://github.com/vuvova/ann-benchmarks/blob/dev/ann_benchmarks/algorithms… For faster inserts you can use M=8 and ef_search=800. Of course, always make sure that the mhnsw_max_cache_size is big enough to hold your entire data set. SIFT1M is rather small, 300M should likely be enough. I'd use at least mhnsw_max_cache_size=1G to be safe, it's an upper limit, MariaDB won't use more memory than necessary anyway. Regards, Sergei Chief Architect, MariaDB Server and security(a)mariadb.org

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MariaDB Day @ Brussels 01.02.2025
by Anna Widenius 05 Jan '25

05 Jan '25

Hi All! We are at it again, MariaDB Day is coming to Brussels 1.02.2025 - https://www.meetup.com/mariadb-server/events/305194675/ MariaDB Day events bring together the MariaDB Foundation and community to celebrate and share the latest developments in MariaDB Server. Theme: Vectors, RAG, and everything new in MariaDB Server. With the imminent GA release of MariaDB Vector in MariaDB 11.7, we’re excited to showcase new functionality, real-world use cases, and the promise of Gen AI capabilities within MariaDB Server. Early previews already point to significant enhancements in both features and performance. Compatibility remains a hallmark of MariaDB Server. In many cases, upgrading from MySQL to the latest MariaDB release is simpler than moving to newer MySQL versions, particularly MySQL 8.0 and later. If you’ve attended previous MariaDB Days, you’ll notice a continuing commitment to our core themes. We see databases as a constant source of innovation—one of the many reasons we love gathering with you around FOSDEM each year. Remember to RSVP - places are limited! 💥 https://mariadb.org/projects/mariadb-vector/ Anna Widenius Chief of Staff, MariaDB Foundation

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Re: Question: Performance impact of adding Nullable FK to a new column in large tables
by Guillermo Céspedes Tabárez 03 Jan '25

03 Jan '25

Hi Jeff, Thank you for your response! To clarify, my question is more hypothetical and focused on understanding how the database engine handles this specific scenario. If the column being added is new and starts with all values as NULL, does it make sense to temporarily disable FOREIGN_KEY_CHECKS during the ALTER TABLE operation? My main concern is whether the database performs any additional checks or processes, even though the column is empty (NULL), or if the operation is already optimized and skipping the checks automatically. I'm not debating the use of foreign keys or their impact on runtime performance. I'm specifically curious if disabling FOREIGN_KEY_CHECKS in this situation saves any resources during the ALTER TABLE, or if it's unnecessary because the database doesn't do anything in this case that would benefit from skipping checks. Best regards, Guillermo El vie, 20 dic 2024 a la(s) 5:14 p.m., Jeff Dyke (jeff.dyke(a)gmail.com) escribió: > > While i'm not really sure what performance issues you are referring to. FK are going to have a small performance hit on row changes, but for data integrity, its what you need. When you start to design FKs with Null values, you are talking some of the work off of the database work that can be done for you, and moving it to your developers. Also parent_id should be indexed to assist in select performance. > > Most times that I have seen this done in the past, its normally removed and the index is kept. if parent_ids are going to be duplicated and only null for a period of time, that is a good one to many relationships, that will enforce integrity once populated. > > If you think this will improve overall performance, that is not the goal of Foreign Keys. > > > On Fri, Dec 20, 2024 at 11:03 AM Guillermo Céspedes Tabárez via discuss <discuss(a)lists.mariadb.org> wrote: >> >> Hi, >> >> I’d like to understand the performance impact of adding a FOREIGN KEY >> constraint to a new column in a large table. If the column is nullable >> and defaults to NULL, does the engine perform any checks or >> validations on existing rows? Or is the operation optimized since the >> column starts with all values as NULL? >> >> Here’s a simplified example: >> >> ALTER TABLE child_table >> ADD COLUMN parent_id INT NULL, >> ADD CONSTRAINT fk_child_parent FOREIGN KEY (parent_id) REFERENCES >> parent_table (id) >> ON UPDATE CASCADE ON DELETE SET NULL; >> >> Both child_table and parent_table are large, and the new column >> (parent_id) is empty initially. >> >> Does adding the foreign key have any measurable performance impact in >> this case? Additionally, would it make sense to temporarily disable >> FOREIGN_KEY_CHECKS for this ALTER TABLE operation and then re-enable >> it? Could this save any resources or improve performance? >> >> Thanks for any insights! >> >> Best regards, >> Guillermo. >> _______________________________________________ >> discuss mailing list -- discuss(a)lists.mariadb.org >> To unsubscribe send an email to discuss-leave(a)lists.mariadb.org

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Re: No Mariadb 10.11 enterprise?
by highclass99 22 Dec '24

22 Dec '24

I did look into purchasing MariaDB Enterprise Server in the past for a service I was helping, but in the end stuck with MariaDB Community Server, because I was worried we might have trouble migrating back to the community server version if needed as the client was not 100% sure they could keep paying for all the instances they needed in the future. If on a certain MariaDB Enterprise version, would it be binary compatible with the same MariaDB Community Server version? (as long as not using features only in the MariaDB Community Server version) Thank you. Have a nice day. On Wed, Dec 18, 2024 at 9:27 PM Sergei Golubchik <serg(a)mariadb.com> wrote: > Hi, highclass99, > > On Dec 14, highclass99 via discuss wrote: > > > > I noticed on https://mariadb.com/docs/server/release-notes/ that after > > MariaDB 10.6 enterprise there is no MariaDB 10.11 enterprise but only > 11.4 > > enterprise release candidate right now. > > > > Does this mean there will be no MariaDB 10.11 enterprise? > > Is there a reason for MariaDB to be skipping the LTS version for > enterprise? > > Yes, it does. Yes, there is. > > While MariaDB Community Server's focus is on rapidly delivering new > features to users - which is why there is a rolling release line, > MariaDB Enterprise Server focus is on stability and long life cycle. > > In other words, MariaDB Enterprise Server is maintained longer and is > not released as often. It still gets new features through carefully > selected backports, see any release notes, e.g. > > https://mariadb.com/resources/blog/mariadb-enterprise-server-q4-2024-mainte… > > At least this is the current model. It might change in the future. > > Regards, > Sergei > Chief Architect, MariaDB Server > and security(a)mariadb.org >

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Question: Performance impact of adding Nullable FK to a new column in large tables
by Guillermo Céspedes Tabárez 20 Dec '24

20 Dec '24

Hi, I’d like to understand the performance impact of adding a FOREIGN KEY constraint to a new column in a large table. If the column is nullable and defaults to NULL, does the engine perform any checks or validations on existing rows? Or is the operation optimized since the column starts with all values as NULL? Here’s a simplified example: ALTER TABLE child_table ADD COLUMN parent_id INT NULL, ADD CONSTRAINT fk_child_parent FOREIGN KEY (parent_id) REFERENCES parent_table (id) ON UPDATE CASCADE ON DELETE SET NULL; Both child_table and parent_table are large, and the new column (parent_id) is empty initially. Does adding the foreign key have any measurable performance impact in this case? Additionally, would it make sense to temporarily disable FOREIGN_KEY_CHECKS for this ALTER TABLE operation and then re-enable it? Could this save any resources or improve performance? Thanks for any insights! Best regards, Guillermo.

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No Mariadb 10.11 enterprise?
by highclass99 13 Dec '24

13 Dec '24

Hi, I noticed on https://mariadb.com/docs/server/release-notes/ that after MariaDB 10.6 enterprise there is no MariaDB 10.11 enterprise but only 11.4 enterprise release candidate right now. Does this mean there will be no MariaDB 10.11 enterprise? Is there a reason for MariaDB to be skipping the LTS version for enterprise? Thank you.

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Support for galera clusters
by Dan O'Reilly 05 Dec '24

05 Dec '24

I can't find a place in the galera docs for a problem I'm having, so asking here. I have a 3 node mariadb Galera cluster (2 db's and an arbitrator node). On the arbitrator, when I start gardb manually and specify the log file as -l "/var/log/gardb.log" all is fine. If I try starting it as a service (RHEL 9) using the LOG_FILE in the config file, it always encounters "Failed to open '/var/log/gardbd.log' for appending: 2 (no such file or directory" I can find ZERO documentation on what's going on there." This is gardb version 26.4.14.r, installed as part of mariadb-server-galera.

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