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  1. WiredTiger
  2. WT-2243

Don't keep transaction IDs pinned for reading from checkpoints

        Details

        • Type: Improvement
        • Status: Resolved
        • Priority: Major - P3
        • Resolution: Fixed
        • Affects Version/s: None
        • Fix Version/s: WT2.7.0
        • Labels:
          None

          Description

          We currently treat all btree cursors the same, and make sure that a transactional context is setup for reads before the cursor is positioned. However, for cursors on checkpoints, this is unnecessary because checkpoints are read-only and thus don't need to distinguish between multiple versions of updates.

          There are several workloads that should be improved by not allocating snapshots when reading from checkpoints, including test/checkpoint and LSM Bloom / merge operations.

            Issue Links

            is depended on by

            Improvement - An improvement or enhancement to an existing feature or task. SERVER-21686 WiredTiger changes for 3.2.0-rc5

            • Major - P3 - Major loss of function.
            • Closed

              Activity

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              xgen-internal-githook Githook User added a comment -

              Author:

              {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'}

              Message: WT-2243 Don't keep transaction IDs pinned for reading from checkpoints.
              Branch: develop
              https://github.com/wiredtiger/wiredtiger/commit/3f306ce74f9dc72c1abc372ec0cc2bedfe96c317

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              xgen-internal-githook Githook User added a comment - Author: {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'} Message: WT-2243 Don't keep transaction IDs pinned for reading from checkpoints. Branch: develop https://github.com/wiredtiger/wiredtiger/commit/3f306ce74f9dc72c1abc372ec0cc2bedfe96c317
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              xgen-internal-githook Githook User added a comment -

              Author:

              {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'}

              Message: WT-2243 Only clear btree cursor flags associated with position.

              Previously, we were clearing the new "no transaction" flag every time a cursor was repositioned.
              Branch: develop
              https://github.com/wiredtiger/wiredtiger/commit/8fe7bb1eceae210d0a9a9166ccfeb835a022a7f0

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              xgen-internal-githook Githook User added a comment - Author: {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'} Message: WT-2243 Only clear btree cursor flags associated with position. Previously, we were clearing the new "no transaction" flag every time a cursor was repositioned. Branch: develop https://github.com/wiredtiger/wiredtiger/commit/8fe7bb1eceae210d0a9a9166ccfeb835a022a7f0
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              xgen-internal-githook Githook User added a comment -

              Author:

              {u'username': u'agorrod', u'name': u'Alex Gorrod', u'email': u'alexander.gorrod@mongodb.com'}

              Message: Merge pull request #2339 from wiredtiger/WT-2243

              WT-2243 Don't keep transaction IDs pinned for reading from checkpoints.
              Branch: develop
              https://github.com/wiredtiger/wiredtiger/commit/39dfd21030ac08e425213f9bc382877dff9458da

              Show
              xgen-internal-githook Githook User added a comment - Author: {u'username': u'agorrod', u'name': u'Alex Gorrod', u'email': u'alexander.gorrod@mongodb.com'} Message: Merge pull request #2339 from wiredtiger/ WT-2243 WT-2243 Don't keep transaction IDs pinned for reading from checkpoints. Branch: develop https://github.com/wiredtiger/wiredtiger/commit/39dfd21030ac08e425213f9bc382877dff9458da
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              xgen-internal-githook Githook User added a comment -

              Author:

              {u'username': u'agorrod', u'name': u'Alex Gorrod', u'email': u'alexander.gorrod@mongodb.com'}

              Message: Merge pull request #2339 from wiredtiger/WT-2243

              WT-2243 Don't keep transaction IDs pinned for reading from checkpoints.
              Branch: develop
              https://github.com/wiredtiger/wiredtiger/commit/39dfd21030ac08e425213f9bc382877dff9458da

              Show
              xgen-internal-githook Githook User added a comment - Author: {u'username': u'agorrod', u'name': u'Alex Gorrod', u'email': u'alexander.gorrod@mongodb.com'} Message: Merge pull request #2339 from wiredtiger/ WT-2243 WT-2243 Don't keep transaction IDs pinned for reading from checkpoints. Branch: develop https://github.com/wiredtiger/wiredtiger/commit/39dfd21030ac08e425213f9bc382877dff9458da
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              xgen-internal-githook Githook User added a comment -

              Author:

              {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'}

              Message: Import wiredtiger-wiredtiger-mongodb-3.2-rc4-41-g8326df6.tar.gz from wiredtiger branch mongodb-3.2

              ref: b65381f..8326df6

              4c49948 WT-2244 Trigger in-memory splits sooner.
              9f2e4f3 WT-2248 WT_SESSION.close is updating WT_CONNECTION_IMPL.default_session.
              a6da10e SERVER-21553 Enable fast-path truncate after splits.
              39dfd21 WT-2243 Don't keep transaction IDs pinned for reading from checkpoints.
              4e1844c WT-2230 multi-split error path.
              cace179 WT-2228 avoid unnecessary raw-compression calls.
              890ee34 SERVER-21619 Don't do internal page splits after a tree is marked DEAD.
              6c7338f WT-2241 Use a lock to protect transaction ID allocation.
              978c237 WT-2234 Coverity analysis warnings.
              Branch: master
              https://github.com/mongodb/mongo/commit/e7181b542b25981db42f74cdaee4e7fc323d3e9d

              Show
              xgen-internal-githook Githook User added a comment - Author: {u'username': u'michaelcahill', u'name': u'Michael Cahill', u'email': u'michael.cahill@mongodb.com'} Message: Import wiredtiger-wiredtiger-mongodb-3.2-rc4-41-g8326df6.tar.gz from wiredtiger branch mongodb-3.2 ref: b65381f..8326df6 4c49948 WT-2244 Trigger in-memory splits sooner. 9f2e4f3 WT-2248 WT_SESSION.close is updating WT_CONNECTION_IMPL.default_session. a6da10e SERVER-21553 Enable fast-path truncate after splits. 39dfd21 WT-2243 Don't keep transaction IDs pinned for reading from checkpoints. 4e1844c WT-2230 multi-split error path. cace179 WT-2228 avoid unnecessary raw-compression calls. 890ee34 SERVER-21619 Don't do internal page splits after a tree is marked DEAD. 6c7338f WT-2241 Use a lock to protect transaction ID allocation. 978c237 WT-2234 Coverity analysis warnings. Branch: master https://github.com/mongodb/mongo/commit/e7181b542b25981db42f74cdaee4e7fc323d3e9d

                People

                • Assignee:
                  michael.cahill Michael Cahill
                  Reporter:
                  michael.cahill Michael Cahill
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                  Dates

                  • Created:
                    Updated:
                    Resolved: