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Restore some comments lost during 15732b34e8 

Michael Paquier
This commit is contained in:
Alvaro Herrera 2014-01-03 13:22:03 -03:00
parent a3b4aeecfe
commit 1a3e82a7f9
2 changed files with 9 additions and 6 deletions
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8
src/backend/catalog/index.c
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@ -1446,9 +1446,11 @@ index_drop(Oid indexId, bool concurrent)
/*
* Now we must wait until no running transaction could be using the
* index for a query. Note we do not need to worry about xacts that
* open the table for reading after this point; they will see the
* index as invalid when they open the relation.
* index for a query. Use AccessExclusiveLock here to check for
* running transactions that hold locks of any kind on the table.
* Note we do not need to worry about xacts that open the table for
* reading after this point; they will see the index as invalid when
* they open the relation.
*
* Note: the reason we use actual lock acquisition here, rather than
* just checking the ProcArray and sleeping, is that deadlock is

7
src/backend/commands/indexcmds.c
View File

@ -651,9 +651,10 @@ DefineIndex(IndexStmt *stmt,
* for an overview of how this works)
*
* Now we must wait until no running transaction could have the table open
* with the old list of indexes. Note we do not need to worry about xacts
* that open the table for writing after this point; they will see the new
* index when they open it.
* with the old list of indexes. Use ShareLock to consider running
* transactions that hold locks that permit writing to the table. Note we
* do not need to worry about xacts that open the table for writing after
* this point; they will see the new index when they open it.
*
* Note: the reason we use actual lock acquisition here, rather than just
* checking the ProcArray and sleeping, is that deadlock is possible if