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[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 13 Jun '10

13 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 13 Jun 2010, 11:55)=-=- High Level Description modified. --- /tmp/wklog.121.old.9380 2010-06-13 11:55:42.000000000 +0000 +++ /tmp/wklog.121.new.9380 2010-06-13 11:55:42.000000000 +0000 @@ -1,18 +1,18 @@ -Currently, DS-MRR doesn't support operation over clustered primary keys. The -reason for this was that - - Clustered primary keys are stored in disk order and so, if the sequence of - ranges is ordered, the reads will already go in disk order (and so DS-MRR's - step of re-ordering reads is not necessary). +Currently, DS-MRR doesn't allow to do MRR scans over clustered primary keys. The +reason for this is that + - Clustered primary keys are stored in disk order, so, if the sequence of + scanned ranges is ordered, the reads will automatically happen in disk + order, and DS-MRR's step of re-ordering reads is redundant. - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. -However, with BKA making the MRR calls, there are cases where DS-MRR over +However, when MRR calls are made by BKA, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and - order them, so that it hits the disk in key order. + order them, so that it hits the disk in key(=disk) order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked @@ -20,3 +20,9 @@ * TODO anything else? +This WL entry is about addressing the above by adding support of DS-MRR over +clustered primary key that would work according to this strategy: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval. + + -=-=(Psergey - Sun, 13 Jun 2010, 09:42)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.5009 2010-06-13 09:42:38.000000000 +0000 +++ /tmp/wklog.121.new.5009 2010-06-13 09:42:38.000000000 +0000 @@ -6,11 +6,12 @@ Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. - If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes - non-trival. Do we need to support this case or support only equality ranges? + non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered - PKs? + PKs? (current decision: No) -* Do we support scanning on a prefix of clustered PK? (seems to be yes?) +* Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix + of clustered PK will not be in disk order. We need to run it with regular mode) -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't allow to do MRR scans over clustered primary keys. The reason for this is that - Clustered primary keys are stored in disk order, so, if the sequence of scanned ranges is ordered, the reads will automatically happen in disk order, and DS-MRR's step of re-ordering reads is redundant. - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, when MRR calls are made by BKA, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key(=disk) order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? This WL entry is about addressing the above by adding support of DS-MRR over clustered primary key that would work according to this strategy: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval. HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? (current decision: No) * Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix of clustered PK will not be in disk order. We need to run it with regular mode) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 13 Jun '10

13 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 13 Jun 2010, 11:55)=-=- High Level Description modified. --- /tmp/wklog.121.old.9380 2010-06-13 11:55:42.000000000 +0000 +++ /tmp/wklog.121.new.9380 2010-06-13 11:55:42.000000000 +0000 @@ -1,18 +1,18 @@ -Currently, DS-MRR doesn't support operation over clustered primary keys. The -reason for this was that - - Clustered primary keys are stored in disk order and so, if the sequence of - ranges is ordered, the reads will already go in disk order (and so DS-MRR's - step of re-ordering reads is not necessary). +Currently, DS-MRR doesn't allow to do MRR scans over clustered primary keys. The +reason for this is that + - Clustered primary keys are stored in disk order, so, if the sequence of + scanned ranges is ordered, the reads will automatically happen in disk + order, and DS-MRR's step of re-ordering reads is redundant. - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. -However, with BKA making the MRR calls, there are cases where DS-MRR over +However, when MRR calls are made by BKA, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and - order them, so that it hits the disk in key order. + order them, so that it hits the disk in key(=disk) order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked @@ -20,3 +20,9 @@ * TODO anything else? +This WL entry is about addressing the above by adding support of DS-MRR over +clustered primary key that would work according to this strategy: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval. + + -=-=(Psergey - Sun, 13 Jun 2010, 09:42)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.5009 2010-06-13 09:42:38.000000000 +0000 +++ /tmp/wklog.121.new.5009 2010-06-13 09:42:38.000000000 +0000 @@ -6,11 +6,12 @@ Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. - If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes - non-trival. Do we need to support this case or support only equality ranges? + non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered - PKs? + PKs? (current decision: No) -* Do we support scanning on a prefix of clustered PK? (seems to be yes?) +* Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix + of clustered PK will not be in disk order. We need to run it with regular mode) -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't allow to do MRR scans over clustered primary keys. The reason for this is that - Clustered primary keys are stored in disk order, so, if the sequence of scanned ranges is ordered, the reads will automatically happen in disk order, and DS-MRR's step of re-ordering reads is redundant. - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, when MRR calls are made by BKA, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key(=disk) order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? This WL entry is about addressing the above by adding support of DS-MRR over clustered primary key that would work according to this strategy: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval. HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? (current decision: No) * Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix of clustered PK will not be in disk order. We need to run it with regular mode) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 13 Jun '10

13 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 13 Jun 2010, 09:42)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.5009 2010-06-13 09:42:38.000000000 +0000 +++ /tmp/wklog.121.new.5009 2010-06-13 09:42:38.000000000 +0000 @@ -6,11 +6,12 @@ Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. - If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes - non-trival. Do we need to support this case or support only equality ranges? + non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered - PKs? + PKs? (current decision: No) -* Do we support scanning on a prefix of clustered PK? (seems to be yes?) +* Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix + of clustered PK will not be in disk order. We need to run it with regular mode) -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? (current decision: No) * Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix of clustered PK will not be in disk order. We need to run it with regular mode) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 13 Jun '10

13 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sun, 13 Jun 2010, 09:42)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.5009 2010-06-13 09:42:38.000000000 +0000 +++ /tmp/wklog.121.new.5009 2010-06-13 09:42:38.000000000 +0000 @@ -6,11 +6,12 @@ Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. - If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes - non-trival. Do we need to support this case or support only equality ranges? + non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered - PKs? + PKs? (current decision: No) -* Do we support scanning on a prefix of clustered PK? (seems to be yes?) +* Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix + of clustered PK will not be in disk order. We need to run it with regular mode) -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( including ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trivial. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? (current decision: No) * Do we support scanning on a prefix of clustered PK? (Yes but scan on prefix of clustered PK will not be in disk order. We need to run it with regular mode) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 12 Jun '10

12 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( ncluding ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trival. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? * Do we support scanning on a prefix of clustered PK? (seems to be yes?) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] Updated (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 12 Jun '10

12 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: -=-=(Psergey - Sat, 12 Jun 2010, 08:39)=-=- High-Level Specification modified. --- /tmp/wklog.121.old.538 2010-06-12 08:39:46.000000000 +0000 +++ /tmp/wklog.121.new.538 2010-06-12 08:39:46.000000000 +0000 @@ -1 +1,16 @@ +Basic idea: DS-MRR scan should be done as follows: +1. Sort incoming keys +2. Use the sorted keys to do a disk-ordered retrieval + +Unresolved questions: + +* The "sort incoming keys" part is trivial when we have only equality ranges. + If we allow ranges of arbitrary form ( ncluding ranges with one endpoint + being infinity or ranges overlapping with one another), sorting becomes + non-trival. Do we need to support this case or support only equality ranges? + +* Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered + PKs? + +* Do we support scanning on a prefix of clustered PK? (seems to be yes?) DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? HIGH-LEVEL SPECIFICATION: Basic idea: DS-MRR scan should be done as follows: 1. Sort incoming keys 2. Use the sorted keys to do a disk-ordered retrieval Unresolved questions: * The "sort incoming keys" part is trivial when we have only equality ranges. If we allow ranges of arbitrary form ( ncluding ranges with one endpoint being infinity or ranges overlapping with one another), sorting becomes non-trival. Do we need to support this case or support only equality ranges? * Can/should we use the fact rowid=={clustered PK value} for InnoDB's clustered PKs? * Do we support scanning on a prefix of clustered PK? (seems to be yes?) ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

1 0

[Maria-developers] New (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 12 Jun '10

12 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] New (by Psergey): Add DS-MRR support for clustered primary keys (121)
by worklog-noreply＠askmonty.org 12 Jun '10

12 Jun '10

----------------------------------------------------------------------- WORKLOG TASK -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- TASK...........: Add DS-MRR support for clustered primary keys CREATION DATE..: Sat, 12 Jun 2010, 08:23 SUPERVISOR.....: Igor IMPLEMENTOR....: COPIES TO......: CATEGORY.......: Client-BackLog TASK ID........: 121 (http://askmonty.org/worklog/?tid=121) VERSION........: Benchmarks-3.0 STATUS.........: Un-Assigned PRIORITY.......: 60 WORKED HOURS...: 0 ESTIMATE.......: 0 (hours remain) ORIG. ESTIMATE.: 0 PROGRESS NOTES: DESCRIPTION: Currently, DS-MRR doesn't support operation over clustered primary keys. The reason for this was that - Clustered primary keys are stored in disk order and so, if the sequence of ranges is ordered, the reads will already go in disk order (and so DS-MRR's step of re-ordering reads is not necessary). - Within DS-MRR implementation, the "get rowids from keys" step is not necessary when using clustered primary key, because in InnoDB/XtraDB clustered primary key values are the rowids. However, with BKA making the MRR calls, there are cases where DS-MRR over clustered primary key is beneficial: * BKA may provide lookup keys that have duplicates and/or are in arbitrary order. In that case, DS-MRR implementation may sort the key values and order them, so that it hits the disk in key order. * When running multi-table join with high @@join_cache_level value (and so, linked join buffers), lack of MRR implementation causes the chain of linked join buffers to break. (TODO and so what? Is that really a problem?) * TODO anything else? ESTIMATED WORK TIME ESTIMATED COMPLETION DATE ----------------------------------------------------------------------- WorkLog (v3.5.9)

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[Maria-developers] Question about License...
by Mateusz Matan 09 Jun '10

09 Jun '10

Welcome, We designed a custom Storage Engine (CLDB) for MySQL/MariaDB which now pass all premature tests. I wonder, how can we solve license problem... We would not share our sources, but we will just use shared library (*.so)... Which licenses should our customer who bought MariaDB with CLDB use to stay legally... If it is possible, can we use in corporation use MariaDB on GPL and just sell CLDB (storage engine) on other license (which one) ?? Thank You for Your quick reply... -- ___________________________________________________________ Mateusz Matan IT Security R&D Department, C/C++ programmer ComArch S.A., Al. Jana Pawła II 41d, 31-864 Kraków tel: (+48 12) 684 8411 e-mail: Mateusz.Matan(a)comarch.pl

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[Maria-developers] per-partition attributes in the CREATE TABLE
by Sergei Golubchik 09 Jun '10

09 Jun '10

Hi, we've talked about engine attributes in the CREATE TABLE, and that one should be able to specify them per partition as well. Now, thinking about it, I'm not quite sure what the semantics shuld be. What is your use case ? How do you want them to work ? I see different possibilities. Say, there is create table ... (.....) XXX=1 partition by list (a) ( partition p0 values in (1) YYY=2, partition p1 values in (2) ); 1. We can say that XXX should be listed in the engine's hton->table_options, and YYY - in the hton->partition_options. this works fine because the engine can use table_share->option_struct and it will contain correct values, independent from whether a table is partitioned or not. but it will break when partitioning will support different engines in different partitions. 2. We can say that XXX is partition engine options, and a pluggable engine can only see YYY. YYY should come from hton->partition_options, and the engine's table level attributes are not applicable. The drawback - every engine needs to have special code to take care of the partitioned case, and to duplicate all table-level options in the partition-level options. 3. Same as 2, but YYY can come from either table level or partition level arrays. Every engine still needs the special code for partitioned case, but does not need to duplicate the table_options array. Regards, Sergei

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