[jira] [Updated] (HADOOP-13430) Optimize and fix getFileStatus in S3A
[ https://issues.apache.org/jira/browse/HADOOP-13430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Steve Loughran updated HADOOP-13430: Assignee: Steven K. Wong > Optimize and fix getFileStatus in S3A > - > > Key: HADOOP-13430 > URL: https://issues.apache.org/jira/browse/HADOOP-13430 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 >Affects Versions: 2.8.0 >Reporter: Steven K. Wong >Assignee: Steven K. Wong >Priority: Minor > Attachments: HADOOP-13430.001.WIP.patch > > > Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 > when pathToKey(f) = key = "foo/bar" is a directory: > 1. HEAD key=foo/bar \[continue if not found] > 2. HEAD key=foo/bar/ \[continue if not found] > 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 > My experience (and generally true, I reckon) is that almost all directories > are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). > Under this condition, request #2 is mostly unhelpful; it only slows down > getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. > The swapped HEAD request will be skipped in practically all cases. > Furthermore, when key = "foo/bar" is a nonempty directory that contains a > "fake directory" file (in addition to actual files), getFileStatus currently > returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping > will fix this. The swapped LIST request will use max-keys=2 to determine > isEmptyDirectory correctly. (Removing the delimiter from the LIST request > should make the logic a little simpler than otherwise.) > Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix > it, I propose skipping request #1 when key ends with "/". The price is this > will, for an empty directory, replace a HEAD request with a LIST request > that's generally more taxing on S3. -- This message was sent by Atlassian JIRA (v6.3.4#6332) - To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
[jira] [Updated] (HADOOP-13430) Optimize and fix getFileStatus in S3A
[ https://issues.apache.org/jira/browse/HADOOP-13430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Steven K. Wong updated HADOOP-13430: Description: Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 when pathToKey(f) = key = "foo/bar" is a directory: 1. HEAD key=foo/bar \[continue if not found] 2. HEAD key=foo/bar/ \[continue if not found] 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 My experience (and generally true, I reckon) is that almost all directories are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). Under this condition, request #2 is mostly unhelpful; it only slows down getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. The swapped HEAD request will be skipped in practically all cases. Furthermore, when key = "foo/bar" is a nonempty directory that contains a "fake directory" file (in addition to actual files), getFileStatus currently returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping will fix this. The swapped LIST request will use max-keys=2 to determine isEmptyDirectory correctly. (Removing the delimiter from the LIST request should make the logic a little simpler than otherwise.) Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix it, I propose skipping request #1 when key ends with "/". The price is this will, for an empty directory, replace a HEAD request with a LIST request that's generally more taxing on S3. was: Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 when pathToKey(f) = key = "foo/bar" is a directory: 1. HEAD key=foo/bar \[continue if not found] 2. HEAD key=foo/bar/ \[continue if not found] 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 My experience (and generally true, I reckon) is that almost all directories are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). Under this condition, request #2 is mostly unhelpful; it only slows down getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. Furthermore, when key = "foo/bar" is a nonempty directory that contains a "fake directory" file (in addition to actual files), getFileStatus currently returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping will fix this. The swapped LIST request will use max-keys=2 to determine isEmptyDirectory correctly. The swapped HEAD request will be skipped if the directory is empty. (Removing the delimiter from the LIST request should make the logic a little simpler than otherwise.) Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix it, I propose skipping request #1 when key ends with "/". The price is this will, for an empty directory, replace a HEAD request with a LIST request that's generally more taxing on S3. > Optimize and fix getFileStatus in S3A > - > > Key: HADOOP-13430 > URL: https://issues.apache.org/jira/browse/HADOOP-13430 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 >Affects Versions: 2.8.0 >Reporter: Steven K. Wong >Priority: Minor > Attachments: HADOOP-13430.001.WIP.patch > > > Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 > when pathToKey(f) = key = "foo/bar" is a directory: > 1. HEAD key=foo/bar \[continue if not found] > 2. HEAD key=foo/bar/ \[continue if not found] > 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 > My experience (and generally true, I reckon) is that almost all directories > are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). > Under this condition, request #2 is mostly unhelpful; it only slows down > getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. > The swapped HEAD request will be skipped in practically all cases. > Furthermore, when key = "foo/bar" is a nonempty directory that contains a > "fake directory" file (in addition to actual files), getFileStatus currently > returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping > will fix this. The swapped LIST request will use max-keys=2 to determine > isEmptyDirectory correctly. (Removing the delimiter from the LIST request > should make the logic a little simpler than otherwise.) > Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix > it, I propose skipping request #1 when key ends with "/". The price is this > will, for an empty directory, replace a HEAD request with a LIST request > that's generally more taxing on S3. -- This message was sent by Atlassian JIRA (v6.3.4#6332) - To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail:
[jira] [Updated] (HADOOP-13430) Optimize and fix getFileStatus in S3A
[ https://issues.apache.org/jira/browse/HADOOP-13430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Steven K. Wong updated HADOOP-13430: Attachment: HADOOP-13430.001.WIP.patch HADOOP-13430.001.WIP.patch - It's a work in progress. Early feedback welcome. > Optimize and fix getFileStatus in S3A > - > > Key: HADOOP-13430 > URL: https://issues.apache.org/jira/browse/HADOOP-13430 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 >Affects Versions: 2.8.0 >Reporter: Steven K. Wong >Priority: Minor > Attachments: HADOOP-13430.001.WIP.patch > > > Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 > when pathToKey(f) = key = "foo/bar" is a directory: > 1. HEAD key=foo/bar \[continue if not found] > 2. HEAD key=foo/bar/ \[continue if not found] > 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 > My experience (and generally true, I reckon) is that almost all directories > are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). > Under this condition, request #2 is mostly unhelpful; it only slows down > getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. > Furthermore, when key = "foo/bar" is a nonempty directory that contains a > "fake directory" file (in addition to actual files), getFileStatus currently > returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping > will fix this. The swapped LIST request will use max-keys=2 to determine > isEmptyDirectory correctly. The swapped HEAD request will be skipped if the > directory is empty. (Removing the delimiter from the LIST request should make > the logic a little simpler than otherwise.) > Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix > it, I propose skipping request #1 when key ends with "/". The price is this > will, for an empty directory, replace a HEAD request with a LIST request > that's generally more taxing on S3. -- This message was sent by Atlassian JIRA (v6.3.4#6332) - To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
[jira] [Updated] (HADOOP-13430) Optimize and fix getFileStatus in S3A
[ https://issues.apache.org/jira/browse/HADOOP-13430?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] Steve Loughran updated HADOOP-13430: Issue Type: Sub-task (was: Improvement) Parent: HADOOP-13204 > Optimize and fix getFileStatus in S3A > - > > Key: HADOOP-13430 > URL: https://issues.apache.org/jira/browse/HADOOP-13430 > Project: Hadoop Common > Issue Type: Sub-task > Components: fs/s3 >Affects Versions: 2.8.0 >Reporter: Steven K. Wong >Priority: Minor > > Currently, S3AFileSystem.getFileStatus(Path f) sends up to 3 requests to S3 > when pathToKey(f) = key = "foo/bar" is a directory: > 1. HEAD key=foo/bar \[continue if not found] > 2. HEAD key=foo/bar/ \[continue if not found] > 3. LIST prefix=foo/bar/ delimiter=/ max-keys=1 > My experience (and generally true, I reckon) is that almost all directories > are nonempty directories without a "fake directory" file (e.g. "foo/bar/"). > Under this condition, request #2 is mostly unhelpful; it only slows down > getFileStatus. Therefore, I propose swapping the order of requests #2 and #3. > Furthermore, when key = "foo/bar" is a nonempty directory that contains a > "fake directory" file (in addition to actual files), getFileStatus currently > returns an S3AFileStatus with isEmptyDirectory=true, which is wrong. Swapping > will fix this. The swapped LIST request will use max-keys=2 to determine > isEmptyDirectory correctly. The swapped HEAD request will be skipped if the > directory is empty. (Removing the delimiter from the LIST request should make > the logic a little simpler than otherwise.) > Note that key = "foo/bar/" has the same problem with isEmptyDirectory. To fix > it, I propose skipping request #1 when key ends with "/". The price is this > will, for an empty directory, replace a HEAD request with a LIST request > that's generally more taxing on S3. -- This message was sent by Atlassian JIRA (v6.3.4#6332) - To unsubscribe, e-mail: common-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: common-issues-h...@hadoop.apache.org
