Db2 – Adaptive compression and HADR

db2db2-luwhigh-availability

I'm looking into adaptive compression. I can't seem to find any information on how HADR is affected when a table is compressed and then reorg:ed. Example

t=mytable
db2 "alter table $t compress yes adaptive";
for i in $(db2 -x "select rtrim(indschema) || '.' || rtrim(indname) from syscat.indexes where rtrim(tabschema) || '.' || rtrim(tabname) = '${t}' order by 1"); do
    db2 "alter index $i compress yes"
done

db2 "reorg table $t resetdictionary";
db2 "reorg indexes all for table $t"
db2 "runstats on table $t with distribution and sampled detailed indexes all";

Question is whether I need to bring down HADR during this process and restart it once finished, or is everything captured in the log, so that HADR can continue?

Best Answer

Both online and offline reorganization are logged and therefore replicated by HADR. By stopping HADR you will simply allow the standby to fall behind the primary, which will cause a large spike in traffic (and potential log space issues on the standby) when you restart HADR. If you don't suffer from network congestion during normal operation, there's no reason to stop HADR during reorganization. If you do, consider dropping the the standby and rebuilding it anew after the REORGs on the primary are complete.

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