Re: PG11 to PG14 Migration Slowness
Hi, Sorry for the delayed response. We have an fdw extension, we started code changes in the extension for PGv14 on 14.3, we just completed code changes, testing and benchmarking. We'll retarget to 14.6 Also we'll take a look at the changes for pg_dump in v15 . Thanks for the advice. Thanks and Regards, Vignesh K. On Thu, 12 Jan 2023 at 21:18, Tom Lane wrote: > Vigneshk Kvignesh writes: > > I'm migrating our existing PG instances from PG11.4 to PG14.3. I > > have around 5 Million Tables in a single database. When migrating using > > pg_upgrade, its taking 3 hours for the process to complete. I'm not sure > if > > its the intended behaviour or we're missing something here. > > There was some work done in v15 to make pg_dump deal better with > zillions of tables. Don't know if you can consider retargeting > to v15, or how much the speedups would help in your particular > situation. > > Why are you using 14.3, when the current release is 14.6? > > regards, tom lane >
Re: PG11 to PG14 Migration Slowness
Hi Vigneshk, > I'm migrating our existing PG instances from PG11.4 to PG14.3. I have > around 5 Million Tables in a single database. When migrating using > pg_upgrade, its taking 3 hours for the process to complete. I'm not sure if > its the intended behaviour or we're missing something here. Thanks for reporting this. I would say this is more or less an expected behaviour. This being said I think we could do better than that. Could you identify the bottleneck or perhaps provide the minimal automated steps (ideally, a script) to reproduce your issue in a clean environment? -- Best regards, Aleksander Alekseev
Re: PG11 to PG14 Migration Slowness
Vigneshk Kvignesh writes: > I'm migrating our existing PG instances from PG11.4 to PG14.3. I > have around 5 Million Tables in a single database. When migrating using > pg_upgrade, its taking 3 hours for the process to complete. I'm not sure if > its the intended behaviour or we're missing something here. There was some work done in v15 to make pg_dump deal better with zillions of tables. Don't know if you can consider retargeting to v15, or how much the speedups would help in your particular situation. Why are you using 14.3, when the current release is 14.6? regards, tom lane
Re: PG11 to PG14 Migration Slowness
On Thu, Jan 12, 2023 at 02:45:41PM +0530, Vigneshk Kvignesh wrote: >Hi, > > I'm migrating our existing PG instances from PG11.4 to PG14.3. I >have around 5 Million Tables in a single database. When migrating using >pg_upgrade, its taking 3 hours for the process to complete. I'm not sure >if its the intended behaviour or we're missing something here. Yes. In fact, you have a good hardware and I would expect longer time on average. > Most of the tables (90%) in 5 Million are foreign tables. On analysis >found that most of the time is spent in pg_dump (~2.3 hours). In pg_dump >getTableAttrs(), dumpTable() functions take the most time, approx 1 hour >each since we're processing table by table. Also, there are no columns >with default values, which if present might take some time. We're using >PG14's pg_upgrade binary for the process. >Since we have all these tables in one database, parallelism doesn't >have any effect here. Can we make binary upgrade for a single database run >in parallel ? > Kindly advise us if we have missed anything here and possible >solutions for this problem. I don't see any problem. Three-hour downtime every three years for such setup... You are lucky you have only that. But you could try some logical replication to the new server version for upgrading, if you really want to bother. (Well, pg- logical is my preferred on that scale, but the three general op- tions are: internal logical replication, pglogical, slony). >So we're not sure on what we missed here. >Have added more info on the process below. >No. of Tables: 5 Million >Time Taken: 3 Hours >Command Used: $PG14_UPGRADE -Uroot -b $PG11_DIR/bin -B $PG14_DIR/bin -d >$PG11_DIR/data -D $PG14_DIR/data -k -r -j32 >Version: PG11.4 to PG14.3 >Environment: CentOS machine (32 cores(Intel), 128GB RAM) > >Thanks and Regards, >Vignesh K.
PG11 to PG14 Migration Slowness
Hi, I'm migrating our existing PG instances from PG11.4 to PG14.3. I have around 5 Million Tables in a single database. When migrating using pg_upgrade, its taking 3 hours for the process to complete. I'm not sure if its the intended behaviour or we're missing something here. Most of the tables (90%) in 5 Million are foreign tables. On analysis found that most of the time is spent in pg_dump (~2.3 hours). In pg_dump getTableAttrs(), dumpTable() functions take the most time, approx 1 hour each since we're processing table by table. Also, there are no columns with default values, which if present might take some time. We're using PG14's pg_upgrade binary for the process. Since we have all these tables in one database, parallelism doesn't have any effect here. Can we make binary upgrade for a single database run in parallel ? Kindly advise us if we have missed anything here and possible solutions for this problem. So we're not sure on what we missed here. Have added more info on the process below. No. of Tables: 5 Million Time Taken: 3 Hours Command Used: $PG14_UPGRADE -Uroot -b $PG11_DIR/bin -B $PG14_DIR/bin -d $PG11_DIR/data -D $PG14_DIR/data -k -r -j32 Version: PG11.4 to PG14.3 Environment: CentOS machine (32 cores(Intel), 128GB RAM) Thanks and Regards, Vignesh K.
