On Fri, Jul 8, 2022 at 8:20 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Fri, Jul 8, 2022 at 5:59 PM Amit Kapila <amit.kapil...@gmail.com> wrote: > > > > On Fri, Jul 8, 2022 at 12:46 PM Masahiko Sawada <sawada.m...@gmail.com> > > wrote: > > > > > > On Fri, Jul 8, 2022 at 3:27 PM Amit Kapila <amit.kapil...@gmail.com> > > > wrote: > > > > > > > > > > > 1. > > > > In ReorderBufferGetCatalogChangesXacts(), isn't it better to use the > > > > list length of 'catchange_txns' to allocate xids array? If we can do > > > > so, then we will save the need to repalloc as well. > > > > > > Since ReorderBufferGetcatalogChangesXacts() collects all ongoing > > > catalog modifying transactions, the length of the array could be > > > bigger than the one taken last time. We can start with the previous > > > length but I think we cannot remove the need for repalloc. > > > > > > > It is using the list "catchange_txns" to form xid array which > > shouldn't change for the duration of > > ReorderBufferGetCatalogChangesXacts(). Then the caller frees the xid > > array after its use. Next time in > > ReorderBufferGetCatalogChangesXacts(), the fresh allocation for xid > > array happens, so not sure why repalloc would be required? > > Oops, I mistook catchange_txns for catchange->xcnt. You're right. > Starting with the length of catchange_txns should be sufficient. >
I've attached an updated patch. While trying this idea, I noticed there is no API to get the length of dlist, as we discussed offlist. Alternative idea was to use List (T_XidList) but I'm not sure it's a great idea since deleting an xid from the list is O(N), we need to implement list_delete_xid, and we need to make sure allocating list node in the reorder buffer context. So in the patch, I added a variable, catchange_ntxns, to keep track of the length of the dlist. Please review it. Regards, -- Masahiko Sawada EDB: https://www.enterprisedb.com/
master-v3-0001-Add-catalog-modifying-transactions-to-logical-dec.patch
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